材料期刊网

通过进行650℃高温时效试验,研究了Tempaloy AA-1钢在时效过程中M23C6合金相的析出与室温力学性能和冲击韧性的关系,并利用扫描电镜和透射电镜对材料在不同时间时效后Tempaloy AA-1的组织结构和室温冲击断口进行观察.结果表明:随着Tempaloy AA-1钢时效时间的增加,逐渐析出M23C6合金相,并稳定地分布在晶界处.Tempaloy AA-1时效500 h后,由于晶界处M23C6碳化物强化作用,屈服强度与抗拉强度达到最大值;时效8 000 h后,晶界处M23C6碳化物颗粒聚集增大,晶界强化作用弱化,Tempaloy AA-1钢的强度略有降低.长期时效后M23C6型碳化物没有发现其过度团聚,因此,Tempaloy AA-1钢仍具有良好的时效冲击韧性.Tempaloy AA-1时效后具有良好的力学性能和冲击韧性是由于材料在长期高温时效后具有良好的组织稳定性.

The relationship between the precipitation of M23C6 carbide and mechanical properties was investigated after the 650℃aging process of Tempaloy AA-1. The microstructure and corresponding fracture surface under impact and ten-sile tests of the Tempaloy AA-1 with 0 ,500 ,1 000 ,5 000 and 8 000 h aging duration were analyzed by scanning elec-tron microscopy and transmission electron microscopy. The results show that the ocuurrence and distribution at grain boundary of M23C6 carbide were found,as the aging time of Tempaloy AA-1 increases. Due to the grain boundary strength-ening,the Tempaloy AA-1 aged for 500 h showed a maximum yield strength and tensile strength. The obvious growth of M23C6 carbide at grain boundaries with increasing aging time to 8 000 h made grain boundary strengthening become weak-en,resulting in a slight decrease of strength. There is no obvious reunion of M23C6 carbide after long time aging,as a re-sult,the Tempaloy AA-1 material still has good ageing impact toughness. The good mechanical properties and impact toughness after aging is due to the good microstructure stability of Tempaloy AA-1 after long time aging.