论文部分内容阅读
利用放电等离子烧结技术制备高密度W-7Ni-3Fe合金,研究了烧结保温时间对合金致密度、物相、显微组织以及力学性能的影响。结果表明,在1200℃烧结5~14 min后,合金均能实现充分致密化,保温时间对相对密度影响较小。合金中的W晶粒随保温时间的延长开始尺寸变化不大,烧结11 min以上才明显长大,但大多数W晶粒尺寸仍小于5μm。烧结时间超过8min,合金中新出现一种灰色的富W组织。随保温时间延长,合金的洛氏硬度下降不大,然而抗弯强度却明显上升。合金弯曲断口形貌在较短保温时间以沿晶断裂为主,粘结相的延性撕裂和W晶粒的解理断裂随烧结时间延长逐渐增多。
The high density W-7Ni-3Fe alloy was prepared by spark plasma sintering. The effects of sintering temperature on the density, phase, microstructure and mechanical properties of the alloy were studied. The results show that after sintering at 1200 ℃ for 5 ~ 14 min, the alloy can be fully densified, and the holding time has little effect on the relative density. The grain size of the W grains in the alloy did not change much with the extension of the holding time, and it grew obviously after 11 min of sintering, but the grain size of most of the W grains was still less than 5 μm. Sintering time more than 8min, the alloy appears a new gray W-rich organization. With the prolongation of holding time, the Rockwell hardness of alloy did not decrease much, but the bending strength increased obviously. The fracture morphology of the alloy is dominated by intergranular fracture in the shorter holding time, and ductile tear of the binder phase and cleavage fracture of the W crystal gradually increase with the increase of the sintering time.