不同应变速率条件下Al67Ti25Mn8金属间化合物的高温拉伸力学行为

研究了Al67Ti25Mn8金属间化合物在高温不同应变速率条件下的拉伸力学行为.结果表明在3．34×10－5-6.68×10－4s－1范围，随着应变速率的降低，材料的屈服强度显著下降，而拉伸塑性明显升高，塑性最高可达到21％；在低应变速率区高拉伸塑性的获得是由于材料在高温变形过程中发生的动态回复和动态再结晶所致；在高温拉伸时Al67Ti25Mn8金属间化合物是以沿晶方式发生断裂在较高应变速率下材料的低塑性沿晶断裂表明Al67Ti25Mn8的晶界结合强度仍较弱

THE HIGH TEMPERATURE TENSILE BEHAVIORS OF Al_(67)Ti_(25)Mn_8 INTERMETALLICS UNDER DIFFERENT STRAIN RATES

The tensile tests of Al67Ti25Mn8 intermetallic compound were performed at 1173 K and at the range of strain rates from 3.34×10-5 to 6.68× 10-4 s-1. The results show that with decreasing strain rates, the yield stress decreases and the tensile ductility increases from 2.8% to 21%. The good high temperature ductility at low strain rates is attributed to dynamic recovery and dynamic recrystallization during deformation. The fractured surfaces of this compound are intergranular, which suggests that the grain boundaries of this alloy are also intrinsic weak.