Wyniki wyszukiwania - Biblioteka Nauki

1

Effect of applied pressure on the quality of squeeze cast parts made from AlSi9Mg alloy

100%

Reguła T. , Sobczak J. J. , Fajkiel A. , Dudek P.

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2011

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tom Vol. 11, iss. 3

55-60

EN

The results of the study of an influence of pressure in the direct squeeze casting process on the physical and mechanical properties of an AlSi9Mg alloy are presented. The specimens were made by casting the tested AlSi9Mg alloy under the conditions of variable squeeze pressure, using a PHM 160c type hydraulic press. Analyzing the results of the experiment, it has been found that, the applied pressure has an important impact on the quality of castings squeezed in liquid state. The effect of squeeze pressure proves the advisability of continuing the application of various liquid-phase methods using external pressure to improve the properties of castings produced.

2

Multi-Objective Optimization of Squeeze Casting Process using Genetic Algorithm and Particle Swarm Optimization

75%

Patel G. C. M. , Krishna P. , Vundavilli P. R. , Parappagoudar M. B.

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2016

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tom Vol. 16, iss. 3

172--186

EN

The near net shaped manufacturing ability of squeeze casting process requiresto set the process variable combinations at their optimal levels to obtain both aesthetic appearance and internal soundness of the cast parts. The aesthetic and internal soundness of cast parts deal with surface roughness and tensile strength those can readily put the part in service without the requirement of costly secondary manufacturing processes (like polishing, shot blasting, plating, hear treatment etc.). It is difficult to determine the levels of the process variable (that is, pressure duration, squeeze pressure, pouring temperature and die temperature) combinations for extreme values of the responses (that is, surface roughness, yield strength and ultimate tensile strength) due to conflicting requirements. In the present manuscript, three population based search and optimization methods, namely genetic algorithm (GA), particle swarm optimization (PSO) and multi-objective particle swarm optimization based on crowding distance (MOPSO-CD) methods have been used to optimize multiple outputs simultaneously. Further, validation test has been conducted for the optimal casting conditions suggested by GA, PSO and MOPSO-CD. The results showed that PSO outperformed GA with regard to computation time.

3

Analiza rozmieszczenia włókien węglowych w kompozycie na osnowie stopu AK7 wykonanego metodą squeeze casting

75%

Konopka Z. , Cisowska M.

Archiwum Odlewnictwa

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2002

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tom R. 2, nr 4

384--389

PL

Badano rozmieszczenie krótkich włókien węglowych w kompozycie na osnowie stopu AK7 wytworzonego metodą squeeze casting. Przedstawiono wskaźnik określający jednorodność rozmieszczenia włókien na podstawie ilościowych pomiarów struktury metodą kwadratów. Stwierdzono wzrost niejednorodności rozmieszczenia włókien w osnowie kompozytu ze wzrostem ich udziału objętościowego.

EN

The distribution of short carbon fibre reinforcement in AK7 alloy matrix composite processed by squeeze casting was studied. The coefficient determining of distribution homogenity of fibres was pressented by means of quadrat method. Increas of non-uniformity distribution of short carbon fibres with fibre volume fraction increasing in composite was observed.

4

Utilization of heat treatment aimed to spheroidization of eutectic silicon for silumin castings produced by squeeze casting

75%

Vanko B. , Stanček L.

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tom Vol. 12, iss. 1

111-114

EN

This paper describes the possibility of using very short periods of solution annealing in the heat treatment of unmodified hypoeutectic silumin alloy AlSi7Mg0,3 casted by method of casting with crystallization under pressure with forced convection (direct squeeze casting process). Castings prepared at different casting parameters were subjected to special heat treatment called SST (Silicon Spheroidization Treatment), which were originally used only for the modified silumin alloys to spheroidization of eutectic silicon. Temperature holding time in solution annealing of T6 heat treatment is limited in the SST process to only a few minutes. It was studied the effect of casting parameters and periods of solution annealing on ultimate strength, yield strength, and especially ductility that in the unmodified silumin alloy castings is relatively low.

5

Manufacturing and microstructure of MMC based on CuZn38Al2Mn1Fe brass strengthened with δ-alumina fibres

63%

Kaczmar J. W. , Granat K. , Pietrzak K. , Naplocha K. , Grodzka E.

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2010

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tom Vol. 10, iss. 1 spec.

411--414

EN

Metal matrix composite materials were manufactured by squeeze casting with CuZn38Al2Mn1Fe brass of porous preforms made of δ-alumina SAFFIL fibres. The microstructure, Brinell hardness and Vickers microhardness of manufactured composite materials were characterized. Preforms with 10 and 20 vol. % of fibres were preheated and infiltrated applying the pressure of 80 MPa. Microscopic observations showed that alumina fibres are uniformly distributed in the MA58 matrix and there was not observed the destroying of ceramic fibres during squeeze casting process. Hardness of composite materials strengthened with 20 vol.% of SAFFIL fibres reached 265 HB. At the boundary of composite material/not strengthened MA58 alloy it was ascertained the filtration and retention of iron compound precipitates caused by the small dimensions of pores in the ceramic preform. The collection of iron phase precipitates at the boundary composite material/ not strengthened MA58 alloy effected in the increase of microhardness in this zone to 352 HV. On the base of SEM observations the conclusion on limited wettability of fibres by liquid MA58 brass was drawn.

6

Bending strength and fracture investigations of Cu based composite materials strengthened with \delta-alumina fibres

63%

Kaczmar J. W. , Granat K. , Naplocha K. , Kurzawa A. , Grodzka E. , Samociuk B.

Archives of Foundry Engineering

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2013

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tom Vol. 13, iss. 2

59--63

EN

Bending strength, thermal and electric conductivity and microstructure examinations of Cu based composite materials reinforced with Saffil alumina fibres are presented. Materials were produced by squeeze casting method applying the designed device and specially elaborated production parameters. Applying infiltration pressure of 90MPa and suitable temperature parameters provided manufacturing of copper based composite materials strengthened with Saffil alumina fibres characterized by the low rest porosity and good fibre-matrix interface. Three point bending tests at temperatures of 25, 100 and 300ºC were performed on specimens reinforced with 10, 15 and 20% of Saffil fibres. Introduced reinforcement effected on the relatively high bending strengths at elevated temperatures. In relation to unreinforced Cu casting strength of composite material Cu – 15vol.% Saffil fibres increase by about 25%, whereas at the highest applied test temperature of 300ºC the improvement was almost 100%. Fibres by strengthening of the copper matrix and by transferring loads from the matrix reduce its plastic deformation and hinder the micro-crack developed during bending tests. Decreasing of thermal and electrical conductivity of Cu after incorporating fibres in the matrix are relatively small and these properties can be acceptable for electric and thermal applications.

7

Prediction of Secondary Dendrite Arm Spacing in Squeeze Casting Using Fuzzy Logic Based Approaches

63%

Patel M. G. C. , Krishna P. , Parappagoudar M. B.

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tom Vol. 15, iss. 1

51--68

EN

The quality of the squeeze castings is significantly affected by secondary dendrite arm spacing, which is influenced by squeeze cast input parameters. The relationships of secondary dendrite arm spacing with the input parameters, namely time delay, pressure duration, squeeze pressure, pouring and die temperatures are complex in nature. The present research work focuses on the development of input-output relationships using fuzzy logic approach. In fuzzy logic approach, squeeze cast process variables are expressed as a function of input parameters and secondary dendrite arm spacing is expressed as an output parameter. It is important to note that two fuzzy logic based approaches have been developed for the said problem. The first approach deals with the manually constructed mamdani based fuzzy system and the second approach deals with automatic evolution of the Takagi and Sugeno’s fuzzy system. It is important to note that the performance of the developed models is tested for both linear and non-linear type membership functions. In addition the developed models were compared with the ten test cases which are different from those of training data. The developed fuzzy systems eliminates the need of a number of trials in selection of most influential squeeze cast process parameters. This will reduce time and cost of trial experimentations. The results showed that, all the developed models can be effectively used for making prediction. Further, the present research work will help foundrymen to select parameters in squeeze casting to obtain the desired quality casting without much of time and resource consuming.

8

Heat treatment of squeezed AlZnMg alloy

63%

Zyska A. , Konopka Z. , Łągiewka M. , Nadolski M.

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tom Vol. 8, iss. 3s

123--126

EN

The examination results concerning strength properties of squeezed and heat treated castings produced of AlZn5Mg alloy have been presented. Experiments have been held for slab castings squeezed under the pressure ranging from atmospheric one to 90 MPa, subsequently heat treated according to the two options: ageing in the temperature of 170°C for 16 h or ageing in the temperature of 120°C for 24 h. The performed examinations have allowed for proving that the better hardening is achieved when the second ageing option is applied, and the optimum properties (Rm exceeding 360 MPa, A5 ≈ 10%) are obtained by heat treatment of the castings squeezed at 30 MPa pressure. Squeezing process changes the α phase solidification morphology and the degree of its refining. A change of structure from the grain one to the cellular-dendritic one occurs. Grain structure comes to existence again after supersaturation and ageing treatment of squeezed castings, but the grain density is significantly greater than for gravity castings.