Thixoforming 7075 aluminium alloys
Thixoforming 7075 aluminium alloys
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DOI：
10.1016/j.msea.2004.05.004
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发表时间：
2005-01-15
期刊：
影响因子：
6.4
通讯作者：
Kapranos, P
中科院分区：
文献类型：
--
作者：
Chayong, S;Atkinson, HV;Kapranos, P
以挤压比为16：1的7075铝合金为原料，研究了高性能铝合金的触变成形性。半固态下的显微组织由被液体包围的细小球形固体颗粒组成。给出了一步、两步和三步感应加热触变成形的实验结果。不良触变成形材料中的典型缺陷（例如液体偏析、未再结晶晶粒造成的流动阻抗和孔隙）与成功触变成形材料一起显示（触变成形温度在615和618摄氏度之间，具有三步感应加热制度）。对于触变成简单石墨模具并热处理至T6条件的材料获得的最高屈服强度和伸长率为478 MPa和6.9%伸长率。在615 ℃触变成250 ℃的工具钢模具时，获得的最高屈服强度和延伸率分别为474 MPa和4.7%（压头速度2000 mm/s）。这些值（特别是强度）接近7075在锻造热处理条件下的值（505 MPa和11%伸长率）。(C)2004 Elsevier B. V.保留所有权利。
Commercially extruded 7075 alloy (extrusion ratio of 16: 1) has been used as a feedstock for thixoforming in order to investigate thixoformability of a high performance aluminium alloy. The microstructure in the semi-solid state consists of fine spheroidal solid grains surrounded by liquid. The results of thixoforming with one step, two-step and three-step induction heating regimes are presented. Typical defects in poorly thixoformed material (e.g. liquid segregation, impedance of flow by unrecrystallised grains and porosity) are shown alongside successfully thixoformed material (thixoforming temperature of between 615 and 618degreesC with a three-step induction heating regime). The highest yield strength and elongation obtained for material thixoformed into a simple graphite die and heat treated to the T6 condition is 478 MPa and 6.9% elongation. For thixoforming at 615 degreesC into a tool steel die heated to 250 degreesC, the highest yield strength and elongation obtained are 474MPa and 4.7% (ram velocity 2000 mm/s). These values (particularly for strength) are approaching those of 7075 in the wrought heat treated condition (505 MPa and 11% elongation). (C) 2004 Elsevier B.V. All rights reserved.