【作者】 范景莲； 祁美贵； 龚星； 刘涛；

【Author】 Fan Jinglian Qi Meigui Gong Xing Liu Tao (State Key laboratory for Powder Metallurgy,Central South University,Changsha410083)

【机构】 中南大学粉末冶金国家重点实验室；

【摘要】 采用以喷雾干燥一热还原的方法制备的纳米级93W-4.9Ni-2.1Fe复合粉末为原料,制备出细晶钨合金。研究了微量稀土掺杂对烧结致密化和显微组织的影响。结果表明:纳米级复合粉末在1380～1410℃之间液相烧结可实现材料的近全致密化,比同种成分的传统钨合金的烧结温度降低了120℃左右,合金的相对密度可达99%以上,且合金的晶粒尺寸为3～5μm。同时研究了93W-4.9Ni-2.1Fe合金在动态压缩状态下的力学行为,结果表明:与传统W-Ni-Fe合金相比,细晶W-Ni-Fe合金在高应变率下具有更高的合金强度和延性,同时能在较低应变率下有形成局部绝热剪切带的倾向,表明细化晶粒能提高W-Ni-Fe合金的强度以及绝热剪切敏感性;同时,添加微量稀土元素Y能提高W-Ni-Fe合金在高应变率下的强度和延性,并且在低应变率下发生绝热剪切,稀土元素Y的添加有利于绝热剪切带的形成。更多还原

【Abstract】 Fine-grain（FG）93W-4.9Ni-2.1Fe alloy containing 0.03%Y₂O₃ is obtained via liquid phase sintering of nano-composite powder prepared by spray drying,subsequent thermal reduction process.The influence of Y₂O₃ on sintering behavior and microstructure were investigated.The results show that the near full densification is realized and finer spherical -shape tungsten grain about 3～5μm in the alloy is obtained during liquid phase sintering in the range of 1380℃to 1410℃,which is 120℃lower than that of the traditional tungsten heavy alloys.Afterwards,Dynamic mechanical properties and dynamic failure are studied by Split Hopkinson experimental device,the formation of adiabatic shear bands is investigated by using Optical Microscope.In comparison with traditional tungsten heavy alloys,the FG fine-grain tungsten heavy alloy possess higher maximal yield strength value and larger elongation value.Grain refinement promotes the tendency to adiabatic shear band（ASB）formation.On the basis of this,adding Y₂O₃ is more beneficial to form obvious ASB at lower strain rate,which indicates self-sharpening effect in tungsten heavy alloys.更多还原