17-4PH钢激光辐照组织的透射电镜微观分析

Analysis on TEM Microstructure of Laser-irradiated 17-4PH Steel

对17-4PH钢进行固溶＋高温时效处理后,再进行激光辐照＋低温时效处理,利用透射电镜（TEM）对每步工艺下材料的微观组织进行了分析.结果表明：17-4PH钢经固溶＋高温时效后,析出强化相ε-Cu和NbC（N）,尺寸介于20~30 nm,并形成逆转变奥氏体;激光辐照＋低温时效后,强化相ε-Cu和NbC（N）的尺寸小于20 nm,位错密度很高,激光辐照时间对组织影响不大.

TEM microstructure of 17-4PH steel has been analyzed respectively after the previous process of solution treatment and high-temperature aging and the following process of laser irradiation and low-temperature aging.Results show that after the previous process,strengthening phases ε-Cu and NbC（N） will precipitate in sizes of 20-30 nm while reversed austenite form;whereas after the following process,the precipitated phases ε-Cu and NbC（N） would be smaller than 20 nm while high dislocation density be observed.The time of laser irradiation effects little on the microstructure of 17-4PH steel.