Ni10Co14钢的二次硬化过程的TEM观察

TEM OBSERVATION OF SECONDARY HARDENING PROCESS IN Ni10Co14 STEEL

用电镜薄膜技术研究了Ｎｉ１０Ｃｏ１４钢的淬火和回火的组织结构，着重研究了强度－回火温度曲线峰值附近的结构。研究表明，Ｍ＿２Ｃ的形核机制是复杂的，它可以在基体位错、马氏体板条边界析出，也可由Ｍ＿３Ｃ的原位转变于铁素体／渗碳体界面形核析出：合金在４４０℃附近回火５ｈ显示出二次硬化峰，具有稳定的高密度位错的马氏体与自基体共格析出的Ｍ＿２Ｃ粒子共同作用是二次硬化的主要组织因素。

The changes of microstructure in the tempering process of the Ni10Co14 steel have been studied by TEM. Special attention has been paid to the microstructures near the peak of the tempering curve. Mo_2C nucleared and grew along dislocation lines, martensitic lath boundaries, and some of them in situ transformed from M_3C at ferrite / cementite interface. The maximum strength in Ni10Co14 steel was achieved when the steel was tempered at 440℃ for 5 h. The strengthening of the steel was mainly attributed to the combination of the delayed dislocation recovery of the martensitic matrix and coherent precipitation of the Mo_2C particle.