Recrystallisation in the Semi-Solid State in 7075 Aluminium Alloy
Recrystallisation in the Semi-Solid State in 7075 Aluminium Alloy
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DOI：
10.1007/s12289-008-0220-z
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发表时间：
2008-04-01
影响因子：
2.4
通讯作者：
Vaneetveld, G.
中科院分区：
文献类型：
--
作者：
Atkinson, H. V.;Burke, K.;Vaneetveld, G.
目前，7000系列铝合金是从锻造状态加工而成的，浪费很大。因此，存在识别有效的近净整形路线的动机。半固态加工就是这样一种潜在的途径。它依赖于具有非枝晶球状微观结构的合金的触变行为。在半固体状态下，材料在剪切时变薄，并将流动以填充模具。当被加工的材料被重新加热时，它会再结晶并进入半固态，形成所需的球形显微组织。在这里，我们研究了7075铝合金从供应的T6条件下重新加热后的球状体形成的早期阶段。这种合金是非常耐再结晶在固态由于存在弥散颗粒钉扎晶界。球状晶粒的出现突然增加。这与第一种液体形成的位置密切相关。在将所供应的材料再加热到约580摄氏度（液体分数类似于5%）时，可以获得完全球形的微观结构。
7000 series aluminium alloys are currently machined from the wrought state with much waste. There is therefore a motivation to identify effective near net shaping routes. Semi-solid processing is one such potential route. It relies on the thixotropic behaviour of alloys with non-dendritic spheroidal microstructures. In the semisolid state the material thins when sheared and will flow to fill the die. When worked material is reheated, it recrystallises and moving into the semi-solid state, the required spheroidal microstructure develops. Here we examine the early stages of spheroid formation in 7075 aluminium alloy reheated from the as-supplied T6 condition. This alloy is very resistant to recrystallisation in the solid state due to the presence of dispersoid particles pinning grain boundaries. There is a sudden increase in the appearance of spheroidal grains. There is a close association with the position of the first liquid to form. On reheating as-supplied material to around 580 degrees C (fraction of liquid similar to 5%), a fully spheroidal microstructure can be obtained.