Microstructural evolution and tensile mechanical properties of thixoformed high performance aluminium alloys
Microstructural evolution and tensile mechanical properties of thixoformed high performance aluminium alloys
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DOI：
10.1016/s0921-5093(03)00528-8
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发表时间：
2003-11-25
期刊：
影响因子：
6.4
通讯作者：
Jones, H
中科院分区：
文献类型：
--
作者：
Liu, D;Atkinson, HV;Jones, H
商业触变成形通常基于常规的铝基铸造合金，例如A356和A357。然而，这些合金不能提供像常规锻造的合金如2000、6000和7000系列或高强度铝铸造合金如201那样高的机械性能。在本文中，201、2014、6082、7075、7010和2014的“修改”版本（3.87重量%）被添加到本文中。Cu，0.6重量%镁，0.14重量% Si）、6082（1.29重量% Si，1.21重量% Mg）和7075（6.01重量% Zn，3.99重量%镁，2.06重量% Cu，0.12重量% Si）触变成形。采用再结晶和部分熔化（RAP）工艺路线和倾斜冷却（CS）浇注工艺路线获得了半固态触变成形坯料。在部分熔化过程中的微观结构演变进行了研究，在温度下的液体量是可比的各种合金。在T6条件下的触变成形零件的拉伸机械性能进行了测定，并与文献中的常规锻造合金和触变成形高性能铝合金的拉伸机械性能进行了比较。触变成形合金201的拉伸性能显示出相对于永久模铸的显著改善，并且具有优化的热处理方案的触变成形合金2014的拉伸性能接近锻造合金2014的拉伸性能，但是具有较低的断裂伸长率。在T6条件下，触变成形的“改性”2014获得了良好的断裂伸长率（19.6%），屈服强度为270MPa，拉伸强度为408MPa。该屈服强度明显低于目标锻制2014值，并且拉伸强度略低。合金6082和“改性”6082的断裂伸长率（24.4%和12.3%）是令人满意的，但屈服强度和拉伸强度需要增加，以达到锻造6082的目标。由再结晶和部分熔融路线生产的原料制成的7075触变成形的拉伸性能略好于由冷却斜坡上生产的原料制成的7075触变成形的拉伸性能。这两条路线给出的值都接近锻造目标7075。“改性”7075和7010的屈服强度和抗拉强度非常接近锻造目标。(C)2003 Elsevier B.V.保留所有权利。
Commercial thixoforming is generally based on conventional aluminum-based casting alloys such as A356 and A357. However, these alloys do not give such high mechanical properties as the alloys that are conventionally wrought such as 2000, 6000 and 7000 series or the high-strength aluminium casting alloys such as 201. In this paper, 201, 2014, 6082, 7075, 7010 and 'modified' versions of 2014 (3.87 wt.% Cu, 0.6 wt.% Mg, 0.14 wt.% Si), 6082 (1.29 wt.% Si, 1.21 wt.% Mg) and 7075 (6.01 wt.% Zn, 3.99 wt.% Mg, 2.06 wt.% Cu, 0.12 wt.% Si) were thixoformed. The recrystallisation and partial (RAP) melting route and the cooling slope (CS) casting route were used to obtain the semi-solid feedstock for thixoforming. Microstructural evolution during partial melting was studied at temperatures where the amounts of liquid were comparable for the various alloys. Tensile mechanical properties of thixoformed parts in the T6 condition were determined and compared with those of conventionally wrought alloys and thixoformed high performance aluminium alloys from the literature. The tensile properties of the thixoformed alloy 201 show a significant improvement over permanent mould casting and the tensile properties of the thixoformed 2014, with an optimised heat treatment schedule, were close to those of forged 2014 but with lower elongation to fracture. Good elongation to fracture (19.6%) was obtained for thixoformed 'modified' 2014 in the T6 condition, with a yield strength of 270 MPa and a tensile strength of 408 MPa. This yield strength is significantly short of the target wrought 2014 value and the tensile strength is a little short. The elongations to fracture (24.4 and 12.3%) are satisfactory for alloy 6082 and 'modified' 6082 but yield strength and tensile strength need to be increased to achieve the wrought 6082 target. The tensile properties for 7075 thixoformed from starting material produced by the recrystallisation and partial melting route are a little better than those of 7075 thixoformed from starting material produced on the cooling slope. Both routes give values close to the wrought target 7075. The yield strength and tensile strength for 'modified' 7075 and 7010 are quite close to the wrought target. (C) 2003 Elsevier B.V. All rights reserved.