挤压态钨合金绝热剪切局域化及微裂纹萌生现象研究

Adiabatic Shear Localization and Microcracks Initiation in an Extruded Tungsten Heavy Alloy

摘要:

研究变形量对挤压态钨合金动态力学行为的影响及钨合金绝热剪切带内的微观开裂行为。结果表明，加载方向垂直于纤维取向时，随变形量由0增加至40.8%，挤压态钨合金绝热剪切敏感性显著增大；由对钨合金绝热剪切带内微观组织的SEM观察可知，靠近绝热剪切带中心处出现在微裂纹且微裂纹萌生于W-M界面及W颗粒内部；进一步的TEM观察可知，剪切带内W-M界面处存在大量的位错塞积，W颗粒中则出现亚晶内部及沿亚晶界扩展的微裂纹

Abstract:

The influence of extrusion deformation ratio on the dynamic mechanical behavior in a tungsten heavy alloy was investigated under uniaxial compression with loading direction perpendicular to the fiber orientation. With extrusion deformation ratio increasing from 0 to 40.8%, the sensitivity of adiabatic shear banding shows an obviously rising tendency. Microcracks could be seen near the centre of the shear band and initiate at the interface of tungsten-matrix as well as the interior of tungsten. Moreover, the observation by the transmission electron microscopy reveals the dislocation pile-ups at the interface of tungsten-matrix and the presence of a microcrack propagating along the boundary and inside of the subgrain in the interior of tungsten within the shear band