90W-7Ni-3Fe合金拉伸力学行为的应变率效应

Effect of Loading Strain Rate on Tensile Behavior of 90W-7Ni-3Fe Alloy

采用CMT4105拉伸试验机对烧结态90W-7Ni-3Fe（90W）合金进行准静态拉伸试验;在较高应变率条件（1600~2000s-1）下,采用套筒加载直拉式Hopkinson拉杆对90W合金进行动态拉伸试验,研究90W合金在不同加载应变率下的拉伸性能及破坏机制。结果表明,在拉伸加载条件下,90W合金具有明显的应变率效应,随着应变率的增加,强度显著提高,材料断裂时的真实应变下降,断裂前吸收的总能量下降。90W合金的破坏机制由钨-钨界面开裂向钨颗粒解理断裂转变。

The quasi-static tensile properties and dynamic tensile properties of as-sintered 90W-7Ni-3Fe （90W） alloy were studied. Quasi-static tensile tests were carried out by a CMT4105 tensile machine at the strain rate of 0.001 s-1, while dynamic tensile tests were carried out by Split Hopkinson Tensile Bar （SHTB） within a higher strain rate range of 1600~2000 s-1. The tensile properties and failure mechanism of 90W alloy at different strain rates were investigated. Results show that under the condition of tensile loading, 90W alloy exhibits an obvious strain rate effect. With the increasing of strain rate, the tensile strength increases obviously, while the critical true strain for fracture and the total energy absorbed by 90W alloy show a decreasing tendency. The failure mechanism of 90W alloy converts from the abruption of W-W boundaries to the cleavage of tungsten grains.