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1

Conformal thermostating of high-pressure die castings with the increased tightness

Figurski Krzysztof, Pasierb Łukasz, Piekło Jarosław, Burbelko Andriy

Polish Technical Review

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2024

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No. 1

2--7

EN

In the paper, the exemplary concept, together with the analysis of the obtained results from the experimental trials of thermostating using the conformal system in the cold-chamber high-pressure die casting process of aluminium alloy, was described. Construction of the experimental system of thermostating channels, mapping the surface of the cavity, as being placed in the core, shaping the internal geometry of casting with a required increased tightness was performed. The results of the numerical simulations for a given case and the results of the experiments and RTG examinations of the castings made on a real system, utilizing the designed cores, performed in increment technology from steel 1.2709 were submitted.

PL

W pracy przedstawiono przykładową koncepcję wraz z analizą otrzymanych wyników z prób eksperymentalnych dla konformalnego układu termostatowania odlewniczej formy wysokociśnieniowej do odlewania zimnokomorowego stopów aluminium. Dokonano konstrukcji doświadczalnego układu kanałów termostatujących odwzorowujących powierzchnię wnęki formy, umieszczonych w rdzeniu kształtującym wewnętrzną geometrię odlewu o wymaganej podwyższonej szczelności, przedstawiono wyniki symulacji numerycznych dla zadanego przypadku oraz wyniki doświadczeń oraz badań RTG odlewów wykonanych na rzeczywistym układzie wykorzystującym zaprojektowane rdzenie wykonane w technologii przyrostowej z stali 1.2709.

2

Wykonywanie połączeń różnoimiennych ze stopów aluminium metodami spawania łukowego i FSW

Węglowska Aleksandra, Rykała Janusz, Pfeifer Tomasz, Pietrzak Jacek

Napędy i Sterowanie

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2024

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R. 26, nr 5

52--56

PL

Przedstawiono wyniki badań spawania TIG i MIG oraz zgrzewania FSW złączy z blach ze stopu aluminium EN AW-6082, EN AW 5754 oraz odlewniczego stopu EN AC-43200. Scharakteryzowano stopy Al-Mg oraz Al-Mg-Si i ich spawalność. W ramach realizowanych badań przeprowadzono dobór warunków spawania i zgrzewania różnoimiennych stopów aluminium. Złącza poddano badaniom wizualnym, metalograficznym makroskopowym, penetracyjnym (złącza spawane) oraz własności mechanicznych w statycznej próbie rozciągania i zginania (złącza zgrzewane FSW). Na podstawie wyników badań realizowanych w Łukasiewicz – GIT oceniono, że jakość złączy spawanych zależy od przygotowania elementów do spawania, natomiast złączy zgrzewanych od parametrów zgrzewania i ustawienia stopów Al w złączu względem ruchu obrotowego narzędzia.

EN

Results of TIG, MIG and FSW welding technologies of joints made of EN AW-6082, EN AW 5754 aluminum alloy sheets and EN AC-43200 casting alloy are presented. This article briefly presents the characteristics of Al-Mg and Al-Mg_Si alloys and their weldability. As part of the research welding conditions for dissimilar aluminum alloys were selected. The joints were subjected to the visual and penetrant tests (TIG, MIG joints), light microscopy examination as well as tensile and bend tests (FSW joints). Based on the test results obtained in Łukasiewicz – GIT, it was found that the quality of arc welded joints depends on the preparation of the elements for welding, while the quality of FSW joints depends on the welding parameters and the positioning of Al alloys in the joint in relation to the rotational movement of the tool.

3

Implementation of technology for high-performance milling of aluminum alloys using innovative tools and tooling

Ostrowski Robert, Szpunar Marcin, Myśliwiec Piotr, Zwolak Marek, Bujny Marek

Advances in Mechanical and Materials Engineering

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2024

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Vol. 41, nr 1

89-101

EN

The research described in the concerns the development and implementation of new clamping technologies used in machining, particularly for thin-walled structural components of aircraft and helicopters. Among other things, the performance of the Schunk Vero-S Aviation clamping system in machining landing gear beams from 7075 T6 aluminum alloy was analyzed, resulting in significant increases in production efficiency and improvements in the geometric quality of machined parts. During experimental research and implementation testing, special chucks were used on the Schunk Vero-S Aviation system for machining the chassis beam. The results showed an improvement in the quality and accuracy of machined parts compared to traditional clamping methods. Increased production efficiency by minimizing scrap and significantly better surface quality and geometric properties compared to conventional clamping. These studies were conducted as part of a project by Ultratech Sp. z o.o. which was implementing a project co-financed by European Funds "Development and implementation of an innovative clamping method for milling processing of thin-walled structural elements of helicopters and airplanes".

PL

Badania opisane w artykule dotyczą rozwoju i wdrażania nowych technologii mocowania stosowanych w obróbce skrawaniem, szczególnie w przypadku cienkościennych elementów konstrukcyjnych samolotów i śmigłowców. Przeanalizowano m.in. wydajność systemu mocowania Schunk Vero-S Aviation w obróbce belek podwozia ze stopu aluminium 7075 T6, co umożliwiło w znacznym stopniu wzrost wydajności produkcji i poprawą jakości geometrycznej obrabianych części. Podczas badań eksperymentalnych i testów wdrożeniowych zastosowano specjalne uchwyty w systemie Schunk Vero-S Aviation do obróbki belki podwozia. Wyniki wykazały poprawę jakości i dokładności obrabianych części w porównaniu z tradycyjnymi metodami mocowania. Zwiększona wydajność produkcji poprzez zminimalizowanie ilości odpadów w postaci braków i znacznie lepszą jakość powierzchni po frezowaniu, oraz właściwości geometryczne w porównaniu do konwencjonalnego mocowania za pomocą zacisków czy imadeł. Badania te zostały przeprowadzone w ramach projektu przez firmę Ultratech Sp. z o.o., która realizowała projekt dofinansowany z Funduszy Europejskich "Opracowanie i wdrożenie innowacyjnej metody mocowania do obróbki frezarskiej cienkościennych elementów konstrukcyjnych helikopterów i samolotów".

4

Analiza możliwości kształtowania rowków za pomocą wysokociśnieniowego strumienia wodno-ściernego w stopie aluminium

Kudelski Rafał

Stal, Metale & Nowe Technologie

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2023

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nr 11-12

30--39

PL

Niekonwencjonalne metody obróbki skrawaniem stały się popularnym rozwiązaniem do obróbki materiałów w przemyśle energetycznym, motoryzacyjnym i lotniczym, szczególnie podczas obróbki materiałów trudnoskrawalnych.

5

Influence of aluminum alloys surface treatment on the durability of glued joints

Kowalik Joanna, Tworek Magdalena, Smaruj Michał

Polimery

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2023

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Vol. 68, nr 10

523--529

EN

The aim of the work was to analyze the method of preparing the aluminum surface in terms of the functional properties of glued joints with the use of one-component polyurethane adhesive. Six methods of surface treatment of EN AW-5251 aluminum alloy were tested. In addition, changes in the shear strength of adhesive joints after environmental exposure were determined. The best surface preparation processes were atmospheric plasma and anodizing.

PL

Celem pracy była analiza sposobu przygotowania powierzchni aluminium pod kątem właściwości użytkowych połączeń klejonych z zastosowaniem jednoskładnikowego kleju poliuretanowego. Zbadano sześć metod obróbki powierzchni stopu aluminium EN AW-5251. Ponadto określono zmiany wytrzymałości połączeń klejonych na ścinanie po ekspozycji środowiskowej. Najlepszym sposobem przygotowania powierzchni była plazma atmosferyczna i anodowanie.

6

Wykonywanie połączeń różnoimiennych ze stopów aluminium metodami spawania łukowego i FSW

Węglowska Aleksandra, Rykała Janusz, Pfeifer Tomasz, Pietrzak Jacek

Maszyny Elektryczne : zeszyty problemowe

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2023

|

Nr 1 (128)

103--107

PL

Przedstawiono wyniki badań spawania TIG i MIG oraz zgrzewania FSW złączy z blach ze stopu aluminium EN AW6082, EN AW 5754 oraz odlewniczego stopu EN AC-43200. Scharakteryzowano stopy Al-Mg oraz Al-Mg-Si i ich spawalność. W ramach realizowanych badań przeprowadzono dobór warunków spawania i zgrzewania różnoimiennych stopów aluminium. Złącza poddano badaniom wizualnym, metalograficznym makroskopowym, penetracyjnym (złącza spawane) oraz własności mechanicznych w statycznej próbie rozciągania i zginania (złącza zgrzewane FSW). Na podstawie wyników badań realizowanych w Łukasiewicz – GIT oceniono, że jakość złączy spawanych zależy od przygotowania elementów do spawania, natomiast złączy zgrzewanych od parametrów zgrzewania i ustawienia stopów Al w złączu względem ruchu obrotowego narzędzia.

EN

Results of TIG, MIG and FSW welding technologies of joints made of EN AW-6082, EN AW 5754 aluminum alloy sheets and EN AC-43200 casting alloy are presented. This article briefly presents the characteristics of Al-Mg and Al-Mg-Si alloys and their weldability. As part of the research welding conditions for dissimilar aluminum alloys were selected. The joints were subjected to the visual and penetrant tests (TIG, MIG joints), light microscopy examination as well as tensile and bend tests (FSW joints). Based on the test results obtained in Łukasiewicz – GIT, it was found that the quality of arc welded joints depends on the preparation of the elements for welding, while the quality of FSW joints depends on the welding parameters and the positioning of Al alloys in the joint in relation to the rotational movement of the tool.

7

Experimental investigations of microstructural and mechanical behaviour of aluminium alloy 7075 hybrid nanocomposites

Kishore K.L., Padal Balaram K.T., Ranga Raju D.

Composites Theory and Practice

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2023

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R. 23, nr 4

226--234

EN

In this paper, the microstructural and mechanical characterisation of hybrid composites with a metal matrix was conducted. Al2O3 nanoparticles and CNTs were added to strengthen an aluminium alloy (AA 7075) using solid-state powder metallurgy. Utilizing XRD analysis and scanning electron microscope (SEM), microstructural characterization was carried out. Uniaxial compression and microhardness testing were performed to determine how the hybrid composites behaved mechanically. The microstructural research revealed that the nanoparticle dispersion in the matrix is uniform. The XRD plots and the Williamson-Hall equation were used to evaluate the crystallite size, lattice strain and dislocation density. In comparison to the base alloy, the composites have better strength and micro hardness.

8

Investigations of CrN/TiO2 coatings obtained in a hybrid PVD/ALD method on Al-Si-Cu alloy substrate

Staszuk Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144622

EN

The paper addresses an important scientific topic from the utilitarian point of view concerning the surface treatment of Al-Si-Cu aluminum alloys by PVD/ALD hybrid coating deposition. The influence of the conditions of deposition of titanium oxide in CrN/TiO2 coatings on their structure and properties, in particular corrosion resistance, were investigated. The TiO2 layer was produced by the atomic layer deposition (ALD) method with a variable number of cycles. Structural investigations were performed using scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), and Raman spectroscopy methods. Electrochemical properties were analyzed using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. The CrN/TiO2 hybrid coating with titanium oxide deposited at 500 ALD cycles showed the best corrosion properties. It was also found that the prerequisite for obtaining the best electrochemical properties was the amorphous structure of titanium oxide in the tested hybrid coatings. The high tribological properties of the tested coatings were also confirmed.

9

Influence of tool pin profile and welding parameters on microstructure and mechanical properties of dissimilar friction stir welded AA2024 to AA7075 alloys

Mohammed H. B., Naemah I. M., Jomah A. J. S., Alrubaiy A. A. A. G.

Archives of Materials Science and Engineering

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2023

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Vol. 124, nr 1

14--24

EN

Purpose: The paper aims to produce aluminium welds in the solid state with good specifications and the least amount of welding defects by using the friction stir welding method (FSW) and different tool pin profiles and welding parameters. The research investigated the mechanical characteristics and microstructure of a friction stir welded dissimilar aluminium alloy (2024-T3 to 7075-0) through thickness produced by varying welding settings and three different FSW tool pin shapes. Design/methodology/approach: The objective is to obtain the welds with the least amount of welding defects in the solid state by using the friction stir welding method (FSW), designing the tool pin profiles, and changing the rotation speeds. Findings: According to tensile strength and micro-hardness tests, tool rotation of 2000 rpm and square pin profile were the best compared to other working parameters. The greatest hardness and highest tensile strength of FSWed dissimilar aluminium joints have been 144 HV and 215 MPa, respectively, when using the square pin profile at a tool rotation speed of 2000 rpm. The hardness and tensile strength of FSWed dissimilar aluminium alloy joints increase with the tool rotation speed. Microstructural observations of the FSWed dissimilar aluminium joints using a square pin profile at the tool rotation speed of 2000 rpm exhibited the weld zone's high weld quality. Additionally, there were no defects in the weld zone. The fracture surface of the FSWed joint indicated a ductile fracture type. Research limitations/implications: With many regions on either side of the weld with varied compositions, microstructures, and characteristics, the resulting welds of dissimilar alloys might result in unsatisfactory weld joints. Practical implications: The weld zone's exceptional weld quality was demonstrated by microstructural investigations of the FSWed dissimilar aluminium connections utilising a square pin profile at a tool rotation speed of 2000 rpm and feed rate of 20 mm per minute. Application in aerospace, shipbuilding and marine, railway, construction, electrical industries, and land transportation. Originality/value: The original value of the paper is the production of welds from dissimilar aluminium alloy (2024-T3 to 7075-0) with the least amount of welding defects by changing the tool pin profiles and tool rotation speeds using the friction stir welding method.

10

Electrochemical corrosion of aluminium alloy AA1050, processed by accumulative roll bonding

Ilieva M. D., Radev R. H.

Archives of Materials Science and Engineering

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2023

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Vol. 124, nr 1

5--13

EN

Purpose: To investigate the changes in corrosion behaviour of severely deformed by accumulative roll bonding aluminium alloy AA1050. Design/methodology/approach: To determine the influence of the accumulative roll bonding on microstructure, texture, and grain size, electron backscattered diffraction was used. Corrosion behaviour was evaluated in a 3.5 wt.% sodium chloride water solution using anodic polarisation. Findings: It was found out that accumulative roll bonding up to eight cycles led to an increase in corrosion rate compared to annealed alloy, but the increase in the number of cycles of accumulative roll bonding from two to eight shows a tendency toward lowering corrosion rates. It has a beneficial influence on pitting corrosion susceptibility. Research limitations/implications: The presented research focuses only on the influence of texture and grain size on severely deformed aluminium alloy AA1050 corrosion. Other factors, such as accumulated during deformation stresses, could also play their role in the corrosion process. Originality/value: The paper reports results on the influence of two factors – texture and grain size, on the corrosion of severely deformed aluminium alloy AA1050. Most reports on the topic include only the influence of texture or grain size.

11

Morphology and Distribution of α-Al and Mn-rich Phases in Al-Si-Mn Alloys under an Electromagnetic Stirring

Mikołajczak P.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

74--87

EN

Convection caused by gravity and forced flow are present during casting. The effect of forced convection generated by a rotating magnetic field on the microstructure and precipitating phases in eutectic and hypoeutectic AlSiMn alloys was studied in solidification by a low cooling rate and low temperature gradient. The chemical composition of alloys was selected to allow joint growth or independent growth of occurring α-Al, α-Al15Si2Mn4 phases and Al-Si eutectics. Electromagnetic stirring caused instead of equiaxed dendrites mainly rosettes, changed the AlSi eutectic spacing, decreased the specific surface Sv and increased secondary dendrite arm spacing λ2 of α-Al, and modified the solidification time. Forced flow caused complex modification of pre-eutectic and inter-eutectic Mn-phases (Al15Si2Mn4) depending on the alloy composition. By high Mn content, in eutectic and hypoeutectic alloys, stirring caused reduction in the number density and a decrease in the overall dimension of pre-eutectic Mn-phases. Also across cylindrical sample, specific location of occurring phases by stirring was observed. No separation effect of Mn-phases by melt flow was observed. The study provided an understanding of the forced convection effect on individual precipitates and gave insight of what modifications can occur in the microstructure of castings made of technical alloys with complex composition.

12

Flow Effect on Si Crystals and Mn-Phases in Hypereutectic and Eutectic Al-Si-Mn Alloys

Mikołajczak Piotr

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

72--86

EN

During mold filling and casting solidification, melt flow caused by gravity is present. Otherwise, forced flow may be a method applied for casting properties improvement. The flow effect generated by an electromagnetic field on the growing phases and a whole microstructure in Al-Si-Mn alloys was studied by slow solidification conditions. The hypereutectic and eutectic alloys were chosen to allow independent growth or joint growth of forming: Si crystals, Mn-rich α-Al15Si2Mn4 phases and Al-Si eutectics. In eutectic alloys, where Mn-phases precipitate as first and only one till solidus temperature, flow decreased number density of pre-eutectic α-Al15Si2Mn4. In the hypereutectic alloys, where Mn-phases grow in common with Si crystals, forced convection increased the overall dimension, decreased number density of pre-eutectic Mn phases and strengthened the tendency to growth in the outside of the sample. In the alloys, where Si crystals grow as first, stirring reduce number density of Si and moved them into thin layer outside cylindrical sample. Also by joint growth of Si crystals and Mn-phases, in hypereutectic Mn/Si alloy, flow moved Si crystals outside, reduced number density and increased the dimension of crystals. Stirring changed also AlSi eutectic spacing, specific surface Sv of α-Al and secondary dendrite arm spacing λ2. The results gave insight of what transformation under stirring take place in simple Al-Si-Mn alloys, and helps to understand what modifications in technical alloys may occur, that finally lead to changes in castings microstructure and properties. The possibility to control dimension, number density and position of Mn-phases and Si crystals is completely new and may help by metallurgical processes, continuous casting of billets and in the production of Si for the solar photovoltaic industry.

13

Zastosowanie zgrzewania tarciowego z przemieszaniem (FSW) do wykonywania połączeń doczołowych wysokowytrzymałych stopów aluminium stosowanych w przemyśle zbrojeniowym

Kosturek Robert

Stal, Metale & Nowe Technologie

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2022

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nr 9-10

38--41

PL

Otrzymywanie wysokiej jakości połączeń spójnościowych umacnianych wydzieleniowo stopów aluminium stanowi jedną z decydujących batalii na froncie rozwoju współczesnej techniki, będąc istotnym motorem postępu przemysłu motoryzacyjnego, lotniczego i zbrojeniowego.

EN

This paper presents selected results of research concerning AA2519-T62 and AA7075-T651 butt joints produced with the FSW technique, including macroscopic observations, microhardness distributions and tensile tests. The applied welding technique enabled obtaining high-quality welds of the 87% and 77% joint efficiencies for AA2519-T62 and AA7075- -T651 respectively.

14

A study of the properties and development in technology for obtaining multi-component systems of particle reinforced aluminum and titanium alloys

Gumen Olena, Selina Irina, Kruzhkova Mariia

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2022

|

Vol. 11

17--21

EN

The article analyzes the groundwork on the influence of alloying contaminants on the structure and mechanical properties of aluminum alloys. Aluminum has become widely used in various parts of machine-building due to its physical properties. However, the main task of modern material science is to increase the strength of aluminum alloys. Therefore, today there is the development of materials and alloys based on aluminum with alloying constituents (copper, silicon, magnesium, zinc, mangan), which are administered in aluminum mainly to increase its strength. Especially attractive are properties of aluminum-doped by transition metals, in particular scandium, zirconium, iron, etc. Finally, conclusions are drawn in order to develop a material based on aluminum with increased hardness, durability, and crack resistance.

15

Adjustment of process parameters in the brazing of aluminium heat exchangers

Mirski Zbigniew, Pabian Jarosław

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2022

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Vol. 66, No. 4

9--20

EN

Brazing in tunnel continuous furnaces constitutes the primary technology used when brazing heat exchangers made of the 3XXX series of aluminium alloys. The pure nitrogen-shielded brazing process is performed using non-corrosive flux NOCOLOK. The primary parameters applied during the brazing of aluminium heat exchangers include brazing temperature and time as well as the type and the amount of filler metals. One of the most commonly used brazing metals (having the form of coatings deposited on elements subjected to brazing) is silumin AlSi7.5. All parameters, significantly affecting the quality of the brazing process, enable the prevention of unfavourable physicochemical phenomena such as the dissolution and the erosion of brazed joints. The article presents results of brazing tests performed using normal, hot and very hot temperature profiles. A wedge test discussed in the article (performed using the normal brazing profile and involving metallographic examination) enabled the determination of the capillarity and wettability of the filler metal. The test also revealed the slight dissolution of materials subjected to brazing, yet within acceptable limit values.

PL

Lutowanie twarde w tunelowych piecach przelotowych jest podstawową technologią spajania wymienników ciepła, wytwarzanych ze stopów aluminium serii 3XXX. Lutowanie odbywa się pod osłoną czystego azotu (99,999%) oraz przy oddziaływaniu niekorozyjnego topnika NOCOLOK. Do podstawowych parametrów lutowania aluminiowych wymienników ciepła zalicza się temperaturę i czas lutowania oraz rodzaj i ilość (grubość plateru) stosowanych materiałów dodatkowych. Jako luty, w postaci platerów naniesionych na łączone elementy, są najczęściej używane spoiwa siluminowe, w tym przede wszystkim spoiwo AlSi7,5. Wszystkie parametry mają bardzo istotny wpływ na jakość procesu lutowania, w tym na uniknięcie niekorzystnych zjawisk fizykochemicznych, takich jak roztwarzanie i erozja połączeń lutowanych. W artykule przedstawiono wyniki prób lutowania, stosując profile temperaturowe: normalny, gorący i bardzo gorący. W próbie klinowej, używając normalnego profilu lutowania, na podstawie badań metalograficznych, określono kapilarność i zwilżalność lutu, a także stwierdzono nieznaczne roztwarzanie materiałów lutowanych, w granicach wartości dopuszczalnych.

16

Effect of Filter Type on Mechanical Properties During Aluminium Alloy Casting

Bruna Marek, Galčík Marek

Archives of Foundry Engineering

|

2022

|

Vol. 22, iss. 3

95--98

EN

The naturally pressurized gating system was used for reoxidation suppression during aluminium alloy casting. A naturally pressurized gating system appears to be a suitable solution to reduce reoxidation processes, which was proven by our previous works. The disadvantage of this system is that without inserting deceleration elements, the melt velocity is supercritical. Therefore, the aim of paper is to find a proper way to reduce the melt velocity, which is the main parameter affecting the scale of reoxidation processes. For the purpose of the melt velocity reduction, labyrinth filters, foam filters and flat filters effect on the melt velocity and the number of oxides were investigated by numerical simulation software in the first stage of the experiment. After simulations observation, the effect of filters on the mechanical properties was investigated by experimental casts. The simulations and experimental casts proved that filters had a positive effect on the melt velocity reduction and it was associated with increased mechanical properties of castings. The best results were achieved by the foam filter.

17

Influence of Fe, Cr, and Cu addition on the microstructure, hardness, and anticorrosion properties of Al-Ni-Y alloys

Babilas Rafał, Młynarek-Żak K., Łoński W., Bukowiec D., Lis M., Kądziołka-Gaweł M., Warski T., Radoń A.

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 2

art. no. e82, 1--15

EN

This study evaluated the structural changes of Al-Ni-(Fe,Cr,Cu)-Y alloys induced by different cooling states. The aim was to determine the role of Fe, Cr, and Cu addition as well as cooling rate on the structure, hardness and anticorrosion properties of crystalline and nanocrystalline Al-Ni-Y alloys. The impact of the preparation method on the structure of alloys was observed by the broadening of the X-ray diffraction peaks of the alloys in the form of plates, which indicated structure fragmentation at a high cooling rate. The TEM images showed the formation of a structure composed of homogeneously dispersed α-Al nanograins. Phase analysis performed using X-ray diffraction method and Mossbauer spectroscopy revealed that the slowly cooled master alloys were mainly composed of Al23Ni6Y4, Al10Fe2Y, and α-Al phases. The Al10Fe2Y structure was the main Fe-bearing phase in all investigated master alloys. A crystallization mechanism was proposed based on the DTA heating and cooling curves. The pitting corrosion type was identified based on morphology observations after electrochemical tests. Rapid solidification and the addition of chromium and copper improved the microhardness as well as corrosion resistance. The high increase of hardness (289 HV0.1) and corrosion resistance[...]

18

Experimental investigation of the novel dieless clinching process free of blank holder

Qin Denglin, Chen Chao, Zhang Huiyang, Ren Xiaoqiang, Wu Jinliang

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 1

art. no. e28, 2022

EN

A novel dieless clinching process free of blank holder was proposed in this study. This novel clinching process applied to joining Al5052 sheets under the forming forces from 24 to 54 kN was investigated experimentally. The joint geometrical characteristics, static mechanical strength, energy absorption and failure modes were revealed. From the results, the sound joints can be produced under various forming forces from 24 to 54 kN. With the forming force increasing, the neck thickness was increased continually while the interlock value remained almost constant. On the other hand, the protrusion height of clinched joint was reduced continually with the forming force increasing. Both the tensile strength and shear strength were enhanced with the forming force increasing. Under the forming force of 54 kN, the tensile strength and the shear strength were 1249 and 1107 kN, respectively. In general, a larger joining force leads to a better clinched joint with lower protrusion height and higher mechanical strength.

19

Effect of single roll drive cross rolling on the microstructure, crystallographic texture, and mechanical behavior of Al–Zn–Mg–Cu alloy

Kazemi-Navaee Amir, Jamaati Roohollah, Aval Hamed Jamshidi

Archives of Civil and Mechanical Engineering

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2022

|

Vol. 22, no. 1

art. no. e41, 2022

EN

In this work, the effect of single roll drive cross rolling on the microstructure, crystallographic texture, hardness, tensile properties, and fracture behavior of AA7075 aluminum alloy was investigated. It was found that with increasing the thickness reduction, the grain size reduced and the average width of grain for the 40% deformed sample decreased to 3.7 ± 0.4 µm. Due to the nature of the cross-rolling process, several X-type shear bands were observed after 40% deformation. The recrystallization texture is notably intensified to its highest value of 4.4 × R, after only 20% cold deformation due to the occurrence of continuous dynamic recrystallization (CDRX). The intensity of recrystallization texture sharply dropped to its lowest value of 2.7 × R. This was due to the rotation of Goss-orientated new grains in the 20% deformed sample toward copper orientation during 40% rolling. With increasing the thickness reduction, the overall texture intensity significantly reduced owing to the nature of the cross-rolling process in which the rolling direction rotates 90° after each 10% strain. Two texture transitions were observed along τ fiber: rolling (copper) texture to recrystallization (Goss) texture after 20% thickness reduction and recrystallization to the rolling texture after 40% deformation. The hardness and strength increased by increasing the thickness reduction, while the ductility decreased. After a 40% thickness reduction, yield strength significantly increased from 138.3 ± 4.4 MPa (for initial sample) to the highest value of 580.5 ± 11.5 MPa, demonstrating 320% increment, in the 0° direction. This increment for 45° and 90° direction was 265% and 337%, respectively. By 40% rolling, the value of in-plane anisotropy (IPA) remarkably decreased to its lowest value of 3.4% due to texture weakening. With increasing the rolling reduction to 20%, the severity of Portevin–Le Chatelier (PLC) increased in the flow curves due to the occurrence of CDRX and also strengthening of the rotated cube {001} < 110 > and E {111} < 110 > components. With increasing the rolling reduction, the size of cleavage facets and the severity of delamination increased, and the number and depth of dimples decreased.

20

Prediction of filler added friction stir welding parameters for improving corrosion resistance of dissimilar aluminium alloys 5052 and 6082 joints

Sasikumar A., Gopi S., Mohan Dhanesh G.

Advances in Materials Science

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2022

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Vol. 22, nr 3(73)

79--95

EN

The aluminium alloys 5052 and 6082 are extensively used in manufacturing lighter structural members, having improved strength and resistance to corrosion. Magnesium (Mg) and Chromium (Cr) powder were the filler materials selected for enhanced corrosion protection properties in this investigation. Friction stir welding (FSW) process parameters viz., spindle speed, welding speed, shoulder penetration, the centre distance between the holes and filler ratio are used to forecast the minimum corrosion rate from different weld regions of AA5052-AA6082 dissimilar joints. Response surface methodology based on a central composite design was used to evolve the mathematical models and estimate dissimilar FSW joints’ corrosion rates. Response optimization shows that the minimum corrosion rate was achieved by the welding parameters of spindle speed 1000 rev/min, welding speed 125 mm/min, holes spacing of 2 mm and filler ratio 95% of Mg and 5% of Cr.