SPS循环热处理对93W-4.9Ni-2.1Fe合金组织和性能的影响

Effect of SPS Cyclic Heat-Treatment on the Microstructure and Properties of 93W-4.9Ni-2.1Fe Alloy

基于放电等离子烧结(SPS)技术对烧结态的93W-4.9Ni-2.1Fe高密度钨合金进行真空循环热处理,并通过光学显微镜、SEM、EDS和三点弯曲实验分析循环热处理对合金的显微组织、成分和力学性能的影响规律。结果表明,随着循环次数的不断增加,粘结相渗入W-W界面不断增多,W-W连接度和二面角不断降低,而钨晶粒尺寸变化较小;粘结相则因W含量的增加得到了固溶强化,进而致使合金的硬度有所提高。合金的抗弯强度在循环2次后明显提高,当循环次数增加到20次后,合金的平均抗弯强度达到2321 MPa,相比液相烧结后淬火处理的合金提高了约160 MPa。因此,SPS循环热处理可以明显改善93W-4.9Ni-2.1Fe高密度钨合金的组织和力学性能。

The effect of vacuum cyclic heat-treatment based on spark plasma sintering（SPS） technique on the microstructure, composition and properties of as-sintered 93 W-4.9 Ni-2.1 Fe tungsten heavy alloy was studied by optical microscope, SEM, EDS and three-point bending tests. The results show that the matrix penetration into W-W grain boundaries increases in amount remarkably, and the W-W contiguity and dihedral angle decrease gradually with the increase of the cycle index. SPS cyclic heat-treatment does not obviously change the micro-hardness and grain size. The matrix is strengthened by the increase of tungsten content owing to the treatment. The bending strength of the alloy is significantly increased after 2 cycles. When the number of cycles is increased to 20, the average bending strength reaches 2321 MPa, which is 160 MPa higher than that of the conventional liquid-sintered and solution-treated 93 W-4.9 Ni-2.1 Fe alloy. The microstructure and properties of 93 W-4.9 Ni-2.1 Fe tungsten heavy alloy can be improved greatly by SPS cyclic heat-treatment.