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Crystallographic Texture and Grain Refinement in the CuCr Alloy Deformed by SPD Method

Urbańczyk-Gucwa A., Brzezińska A., Adamczyk-Cieślak B., Rodak K.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 4

1563--1568

EN

Microstructure and texture of the CuCr0.6 alloy processed by rolling with cyclic movement of rolls (RCMR) at room temperature were investigated. The RCMR processing was applied for the samples in different initial conditions in the solid solution followed by quenching into iced water at 1000°C for 3 h and in aging treatment conditions performed at 500°C for 2 h and at 700°C for 24 h. Application of the solution and aging processes prior to RCMR deformation results in the partial dissolution of Cr particles into the Cu matrix and precipitation of the second phase particles. RCMR processing with value of the total effective strain (εft) of 5 was introduced to the material. It was found that the RCMR method is effective in texture weakening. The obtained results revealed that there is a large similarity in texture orientations after RCMR processing independently of heat treatment conditions. Cyclic character of deformation leads to an incomplete transition of LAB to HAB.

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Rozdrabnianie struktury stopu CuCr0,6 za pomocą metod KoBo i COT

Brzezińska A., Rodak K.

Obróbka Plastyczna Metali

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2018

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T. 29, nr 4

369--380

PL

Prezentowana praca ma na celu scharakteryzowanie zmian struktury zachodzących w stopie miedzi CuCr0,6 (C18200) po zastosowaniu dwóch metod cyklicznego odkształcania: metody wyciskania z obustronnie skrętną matrycą KoBo oraz ściskania z oscylacyjnym skręcaniem COT. Procesy odkształcania zastosowano na materiale umacnianym roztorowo (po przesycaniu) oraz na materiale umocnionym wydzieleniowo (po przesycaniu i starzeniu). Wykazano, że zastosowanie cyklicznych metod SPD umożliwia rozdrobnienie struktury do poziomu ultradrobnoziarnistego, jednakże efekty rozdrobnienia struktury zależą od zastosowanej metody. W wyniku odkształcania COT większość otrzymanych struktur to podziarna o małych kątach dezorientacji i dużej gęstości dyslokacji wewnątrz ziaren. Natomiast po zastosowaniu KoBo w strukturze obecne są dyslokacje wewnątrz ziaren zrekrystalizowanych. Badania wykonano przy użyciu skaningowo-transmisyjnego mikroskopu elektronowego STEM Hitachi HD-2300A. Do analizy ilościowej skorzystano z programu Metilo. Pomiary mikrotwardości przeprowadzono przy użyciu mikrotwardościomierza Future-Tech FM-700 przy obciążeniu 0,1 kg. Właściwości mechaniczne po zastosowaniu KoBo oceniono w oparciu o statyczną próbę rozciągania przeprowadzoną na maszynie Instron 4505/5500R. Właściwości mechaniczne po zastosowaniu COT określono w oparciu o statyczną próbę rozciągania mikropróbek na urządzeniu MST QTest/10.

EN

The paper presents characterize structure of the copper alloy CuCr0.6 (C18200) after applying two methods of cyclic deformation: the method of extrusion with the rotating matrix KoBo and compression with oscillatory torsion. The deformation processes were applied on the material after solution and solution and aging.(after saturation and aging). Shown that applied the SPD metod allows on the fragmentation struture but effects of the framgentation on the structure depends on the method used. As a result of COT deformation, most of the structures obtained are grains with small disorientation angles and high dislocation density inside the grains. After KoBo has been applied to the structure is present in the distribution of recrystallised grains. The test was carried with the use of scanning transmission electron microscope STEM Hitachi HD-2300A. The Metilo programme was used for quantitative analysis. The Future-Tech FM-700 machine was used to perform hardness measurements. The hardness of alloys under a load of 0.1 kg was tested. The mechanical properties after the application of KoBo were evaluated on the basis of a static tensile test carried out on an Instron 4505/5500R machine. Mechanical properties after the application of the COT, the tensile strength of the micro samples was determined on the basis of a static tensile test on the MST QTest/10.

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Influence of Solid Solution and Aging Treatment Conditions on the Formation of Ultrafine-Grained Structure of CuCr0.6 Alloy Processed by Compression with Oscillatory Torsion

Urbańczyk-Gucwa A., Brzezińska A., Rodak K.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

2061--2066

EN

The samples of the CuCr0.6 alloy in the solution treated and additionally in aging states were severely plastically deformed by compression with oscillatory torsion (COT) method to produce ultrafine – grained structure. The samples were processed by using process parameters as: frequency of torsion (f = 1.6 Hz), compression speed (v = 0.04 mm/s), angle torsion (α = ±6°), height reduction (Δh = 7 mm). The total effective strain was εft = 40. The microstructure has been analyzed by scanning transmission electron microscope (STEM) Hitachi HD-2300A equipped with a cold field emission gun at an accelerating voltage of 200 kV. The quantitative microstructure investigations as disorientation angles were performed using a FEI INSPECT F scanning electron microscope (SEM) equipped with a cold field emission gun and a electron backscattering diffraction (EBSD) detector. The mechanical properties were determined using MST QTest/10 machine equipped with digital image correlation (DIC). The COT processed alloy previously aged at 500°C per 2h shows high mechanical strength, ultimate tensile strength UTS: 521 MPa and yield tensile strength YS: 488 MP attributed to the high density of coherent precipitates and ultrafine grained structure.

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Changes in Structure of CuCr0.6 Alloy After Repetitive Corrugation Process

Jung T., Kwaśny W., Rdzawski Z., Głuchowski W., Matus K., Pawlyta M., Szindler M.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 4

2441--2448

EN

This paper presents the study of repetitive corrugation process influence on the strengthening of annealed alloy. Based on the results of mechanical properties of deformed sample, it has been found that the microhardness, ultimate tensile strength, yield strength and apparent elastic limit are significantly increased in relation to annealed sample. Examination on transmission electron microscopy confirmed the effect of intensive plastic deformation on structure fragmentation in the nanometric scale. This work confirmed the possibility of using the repetitive corrugation process to increase mechanical properties of CuCr0.6 alloy.