循环热处理对93W–5Ni–2Fe高比重钨合金冲击韧性的影响

采用粉末冶金法制备成分（质量分数）为93W?5Ni?2Fe的高比重钨合金试样，对高比重钨合金试样进行循环1200 ℃真空热处理+淬火热处理，通过冲击韧性测试和扫描电镜断口形貌分析，研究了同一热处理工艺下，循环热处理次数对高比重钨合金冲击韧性的影响。结果表明:随着循环热处理次数的增加，材料的冲击韧性逐渐升高，第4次循环热处理后冲击韧性达到115 J·cm?2，当进一步增加循环热处理次数后，材料的冲击韧性不再有明显变化；高比重钨合金的冲击断口由第1次热处理后多为钨晶粒解理断裂，逐步过渡为钨晶粒之间粘接相的韧性断裂。

Effect of cyclic heat treatment on impact toughness of 93W–5Ni–2Fe tungsten heavy alloy

The 93W?5Ni?2Fe tungsten heavy alloys (WHAs) were prepared by powder metallurgy method, and then subjected to the cyclic vacuum heat treatment at 1200 ℃ and the oil quenching rapid cooling. The impact toughness of WHAs treated by the same heat treatment was studied by the impact toughness test and the fracture morphology analysis. The results show that, with the increase in the cycle number of heat treatment, the impact toughness of WHAs increases gradually, and the impact toughness reaches 115 J·cm?2 after the fourth cycle heat treatment. However, the impact toughness of WHAs does not change significantly when the cycle number of heat treatment is further increased. The impact fracture of WHAs is mainly cleavage fracture of tungsten grains after the first cycle heat treatment, and then gradually transitions to the ductile fracture of the cohesive phase between tungsten grains.