铝铁合金半固态变形的组织演变

Microstructure evolution of Al-Fe alloy in semi-solid compression deformation

对电磁搅拌的铝铁合金在半固态温度条件下用INSTRON-5500R实验机进行单向压缩实验,实验结果表明,铝铁合金在半固态温度变形时,随着变形温度的升高,真应力峰值降低;随着应变速率增加,真应力峰值也增加,随后会发生应变-软化现象。应变速率愈小,软化过程愈长,应力下降愈缓慢。变形试样中心和边缘区域的变形情况不同,中心区域固相颗粒的变形程度大于边缘区域。在不同的变形量、变形温度和变形速率下,其内部固-液两相的流动方式和变形机理不同。固相主要集中在试样的心部发生塑性变形,而液相则流向边部,其组织形貌与变形温度、变形量和变形速率都有直接的关系。

The unidirectional compression deformation of electromagnetic stirred Al-Fe alloy in the semi-solid state has been stud- led on the material testing machine INSTRON-5500R. The experimental results show that at the deformation in the semi-solid state, thc peak value of the true stress of Al-Fe alloy reduces with the increasing of deformation temperature and increases with the increase of strain rate. Then strain-softening phenomenon would happen. The smaller the strain rate, the longer the softening proceeding and the slower the declining of the stress. The deformation behavior of Al-Fe alloy at centre zone is different with edge zone. The deformation degree of solid phases at centre zone is larger than that at edge zone. The flowing mode and the deformation mechanism of solid and liquid phases in Al-Fe alloy are different with different deformation degree, deformation temperature and deformation rate. The plastic deformation of the solid phases is engendered mainly at the centre zonc with the liquid phases flow to the edge zone. The microstructure morphology has close relationship with the temperature, degree and rate of deformation.