挤压温度对Mg-1Gd合金织构演变的影响

Effects of Extrusion Temperature on Texture Evolution in Mg-1Gd Alloy

采用电子背散射衍射(EBSD)分析方法观察了Mg-1wt%Gd合金在退火过程中的织构演变,研究了挤压温度和退火温度对微观组织及织构的影响。结果表明:在低温挤压下,剪切带形核是主要的再结晶机制,退火后形成了很强的<2>织构类型;而在高温挤压下,剪切带数量较少,退火后织构几乎没有发生变化。因此,剪切带上的形核及<2>晶粒的择优取向生长是Mg-1Gd合金中<2>织构形成的主要原因。

The texture evolution of Mg-1 wt%Gd alloy during annealing was observed by electron backscatter diffraction （EBSD）. The effects of extrusion and annealing temperatures on the microstructure and the texture evolution were studied. The results show that： at lower extrusion temperature, shear band nucleation is the main mechanism of recrystallization, and a strong 〈2111〉 texture type is formed after annealing; however, at high extrusion temperature, the number of shear bands is fewer, and the texture is almost unchanged after annealing. Therefore, the nucleation and the preferred orientation growth of the 〈2111〉 grains in the shear band are the main reasons for the formation of the 〈2111〉 texture in Mg-lGd alloy.