微波烧结钨合金挤压棒材的微观结构及动态力学性能研究

Microstructure and Dynamic Mechanical Properties of Extruded Tungsten Alloy Rods by Microwave Sintering

采用分离式Hopkinson动态压缩装置对微波烧结93W-4.9Ni-2.1Fe合金棒材切割试样进行了动态力学性能研究,采用扫描电镜、光学电镜和纳米压痕硬度仪分别对合金试样微观组织和显微硬度进行了表征和测试。结果表明:微波烧结试样在受到冲击压缩时,钨晶粒与粘结相都发生均匀变形;应变率为2200s-1时,合金的最大应力为2587MPa,钨晶粒和粘结相显微硬度分别为8.716和6.267GPa;当应变速率为2200s-1时合金粘结相变形产生明显热软化效应,在与冲击力呈45°的方向形成了绝热剪切带,位于剪切带中心区域的钨晶粒沿其扩展方向发生变形被拉成纤维状。

The dynamic mechanical properties of 93W-4.9Ni-2.1Fe alloy rod by microwave sintering were investigated under dynamic compression using Split Hopkinson Pressure Bar. The microstructure and micro-hardness of the samples after dynamic compression were analyzed and tested by Scanning Electron Microscope （SEM）, Optical Microscopy（OM） and Ultra Nano Hardness Tester （UNHT）. The results show that tungsten grains and binder phase of the microwave sintered alloy deform uniformly during impact compression. When the strain rate is 2200 s^（-1）, the stress of 93W-4.9Ni-2.1Fe alloy is 2587 MPa, and micro-hardness of tungsten grains and binder phase are 8.716 GPa and 6.267 GPa, respectively. When the strain rate is 2200 s^（-1）, a thermal softening effect is formed due to binder phase deformation, and the adiabatic shear band pears along 45° with the direction of the impact force. Within the center of the bands, the tungsten grains are severely elongated to be fibrous along the propagation directions of the adiabatic shear bands.