原位生成Al_3Zr/6063Al复合材料的高应变速率超塑性（英文）

High Strain Rate Superplasticity of in situ Al_3Zr/6063Al Composites

采用熔体直接反应法,原位制备5%Al_3Zr/6063Al质量分数复合材料。在450℃进行70%变形量锻造预处理,然后进行搅拌摩擦大塑性加工,通过XRD、SEM、EDS、超景深及TEM等分析测试方法研究其高应变速率超塑性。结果表明,通过锻造和搅拌摩擦加工处理后,复合材料的平均晶粒尺寸小于10μm。在350~500℃,初始应变速率为1.0×10^(-3)~1.0×10^(-1)s^(-1)范围内,复合材料均呈现超塑性。在500℃,初始应变速率为1.0×10^(-2)s^(-1),延伸率达到最大值330%,反应敏感指数m值为0.45。分析超塑性变形的主要机制是动态连续再结晶与晶界、位错滑移共同协调完成。

In situ 5wt%Al3Zr/6063 Al composites were fabricate by a direct melt reaction method（DMR） and then processed by deformation pretreatment. Process of the pretreatment was forging of 70% deformation at 450 °C and friction stir processing（FSP）. The high strain rate superplasticity of the composites was studied by modern analytic determination methods. The results show that the average grain size of the composites is less than 10 μm after forging and FSP. The composites exhibit superplasticity at the temperature from 350 to 500 °C and initial strain rate from 1.0×10-3 s-1 to 1.0×10-1 s-1. The elongation reaches 330% and the sensitive index（m value） is 0.45 at the initial strain rate of 1.0×10-2 s-1 and the temperature of 500 °C. The dominant mechanisms of superplastic deformation are grain boundary sliding and dislocation slip which is synergized with moderate grain growth and dynamic continuous recrystallization.