冲击加载条件下化学气相沉积高纯钨的塑性变形机制  

Plastic Deformation Mechanism of High Pure Tungsten Prepared by CVD Method at High Strain Rate

作　　者：谭成文[1] 孙红婵[2] 于晓东[2] 李树奎[2] 王富耻[2] 才鸿年[1] 

机构地区：[1]北京航空航天大学,北京100083 [2]北京理工大学,北京100081

出　　处：《稀有金属材料与工程》2007年第1期100-103,共4页Rare Metal Materials and Engineering

摘　　要：采用较低温度下的化学气相沉积技术制备了高纯钨,利用分离式HOPKINSON压杆装置对制备的高纯钨和商用粉末烧结纯钨进行应变率为1000/s^2000/s的冲击加载,对冲击后的样品进行了变形机制对比分析。结果表明:在冲击载荷作用下粉末烧结纯钨变形机制以滑移和晶界滑动为主,而化学气相沉积纯钨则是孪生变形起到很大的作用;临近孪生间的交互作用会产生2种类型的穿晶断裂,这是化学气相沉积纯钨致脆的原因;在低于103/s应变率量级化学气相沉积纯钨不会发生绝热剪切,难以与钨合金一样通过绝热剪切变形提高其塑性变形能力。High pure tungsten （W, 99.99%） were prepared by chemical vapor deposition （CVD）, then high pure tungsten and polycrystalline tungsten prepared by powder metallurgy （PM） process were impacted using Split Hopkinson Bar （SHB） over a narrow range of strain rates, 1000 s^-1-2000 s^-1. The deformation mechanisms were analyzed by optical microscope （OM）. The results show that the main deformation mechanisms of the polycrystalline tungsten prepared by Powder Metallurgy Process are slip and grain-boundary slide, while those of high pure tungsten are slip, twinning deformation and grain-boundary slide. The interaction between the neighbouring twinnings may induce two kinds of intergranular cracks, which is the key reason of the high pure tungsten em-brittleness. The adiabatic shear band （ASB） is not found for the high pure tungsten under the strain rate in this paper e.g. lower than 103 s^-1, so the plastic deformation ability of the high pure tungsten can not be improved as that of tungsten heavy alloy （WHA）.

关 键 词：化学气相沉积 高纯钨 变形机制 穿晶断裂 

分 类 号：TF124.5[冶金工程—粉末冶金]