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

摘要:

本文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晶粒界面不断增多,W-W连接度和二面角不断降低,显微硬度和晶粒尺寸变化较小,粘结相则因W含量的增加得到了固溶强化。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。

Abstract:

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