时效处理对Co基合金堆焊重熔层组织和性能的影响

通过金相、扫描电镜显微组织分析, 显微硬度测定, 高温磨损试验, 对经不同工艺参数时效处理的Co基合金堆焊重熔层进行了分析研究。结果表明, 堆焊重熔层组织主要是细小的等轴状枝晶γ-Co及其间分布的共晶组织; 经时效处理后, 主要是γ-Co基体上弥散分布着合金碳化物和骨架状的共晶组织。在时效处理时, 随着时效温度的不断提高, 堆焊重熔层表面硬度随之升高, 在900 ℃时硬度达到最大值, 然后急剧下降; 相比较, 经长时(12 h)时效处理的堆焊重熔层硬度高于经短时(6 h)时效处理。经时效处理的堆焊重熔层高温耐磨性均优于未经时效处理的堆焊重熔层, 并且经短时(6 h)时效处理的堆焊重熔层的高温耐磨性好于经长时(12 h)时效处理。

The Effect of Aging Treatment on Structure and Properties of Remelted Hardface Layer of Co-based Alloy

By means of optical microscope (OP), scanning electron microscope (SEM), hardness test and high temperature wear test, remelted hardface layers of Co-based alloy with different aging temperatures and time were studied. The results showed that, the remelted hardface layer was composed of fine dendrite (γ-Co) and eutectic. While aging treatments were made, the microstructure was made up of the framework-like eutectic and the matrix (γ-Co) distributed with carbide. The hardness increased steadily, which reached the maximum at temperature of 900 ℃, and then decreased rapidly with aging temperature enhanced. The hardness values of the remelted hardface layers with longer time's (12 h) aging treatment was higher than that with shorter time (6 h). The test of high temperature wear showed that, after aging treatment, the wear resistance was better than that as remelted. And the wear resistance of remelted hardface layer with aging short time (6 h) is better than that with longer aging time (12 h).