喷射成形Al-22Si-5Fe合金的热变形行为及组织稳定性

来源期刊：金属学报2010年第7期

论文作者：蔡元华 梁瑞光 苏占培 张济山

文章页码：814 - 820

关键词：Al-22Si-5Fe合金； 喷射成形； 热变形； 组织稳定性； Z参数

Key words：Al-22Si-5Fe alloy； spray forming； hot deformation； microstructural stability； Z parameter

摘    要：采用Gleeble-1500热模拟试验机在变形温度为573-723K,应变速率为0.005-0.05 s^-1,最大变形量为30%的条件下对喷射成形Al-22Si-5Fe合金进行热模拟实验,同时利用OM和XRD对其组织稳定性进行了研究.结果表明,过共晶Al-22Si-5Fe合金的热变形行为同样可用包含Zener-Hollomon参数的模型来处理;低温变形时,沉积合金的变形激活能与纯Al的自扩散激活能一致,较高温度下的变形激活能明显高于纯Al的自扩散激活能,说明沉积合金中大量的第二相对变形会产生显著的影响;较低温加热时,沉积合金中的Si颗粒变化不明显,当加热温度在698 K或以上温度时,过共晶Al-22Si-5Fe沉积合金中的Si颗粒将明显长大;在整个实验温度范围内,富Fe的金属间化合物颗粒几乎未发生变化.

Abstract: Hot deformation behavior of spray forming Al-22Si-5Fe alloy at different deformation temperatures with isothermal constant strain rates of 0.005,0.01,0.03,and 0.05 s^-1 was investigated by using Gleeble-1500 thermo-mechanical simulator,with maximum strain of 30%,the microstructures were studied by using of OM and XRD method.The experimental results showed that the hot deformation behavior of spray formed alloy could also be described by a model containing Z parameter (Zener-Hollomon parameter).The calculated deformation activation energy of the studied alloy was consistent with the self-diffusion activation energy of Al atoms at lower deformation temperature,and much higher than the self-diffusion activation energy of Al atoms at higher temperature because of the influences of large content hard constitutes such as prime Si and Fe-bearing intermetallics.The Si particles changed little when deformed at low temperature,but coarsened obviously when deformed at elevated temperature of 698 K or above.The heating temperature had no obvious effect on the sizes of Fe-bearing intermetallics.