摘要
通过Thermo-Calc热力学软件计算、光学显微镜、扫描电镜及透射电镜对0Cr19Mn21Ni2N奥氏体不锈钢在800℃等温时效过程中碳化物、氮化物的析出机制进行了研究。结果表明：第二相碳化物、氮化物析出的成分、种类、分布随局部C元素贫化而发生变化。在800℃等温时效过程中,当时效时间为10～60 min时,晶界上较高浓度的C元素偏析、较大的晶格错配能和畸变能为M_（23）C_6首先在晶界位置形核并形成连续析出颗粒提供充足的热力学和动力学条件;随着时效时间进一步延长,由于碳化物M_（23）C_6的较多析出导致该析出区域C元素逐渐贫化,M_（23）C_6析出的热力学和动力学条件逐渐受到抑制,氮化物Cr_2N开始在晶界析出的M_（23）C_6碳化物附近形核。随后,片层状Cr_2N逐渐在相邻晶粒内长大,其生长方向与奥氏体晶格取向具有固定的位向关系。
Precipitation mechanism of 0Cr19Mn21Ni2N austenitic stainless steel during isothermal aging at 800 ℃ was investigated with Thermal-Calc software thermodynamic calculation, optical microscopy, scanning electron microscopy and transmission electron microscopy. The test results show that the consititution, species and distribution of the carbides and nitrides change with the local reducing of carbon atom. The M23 C6 precipitate nucleation appears at grain boundaries after aging at 800 ℃ for 10-60 min, because of the carbon atom segregation at grain boundaries and the higher distortion energy and lattice misfite energy. As the aging time prolonging, M23 C6 precipitation is inhibited because of the carbon atom depletion and Cr2 N precipitate nucleation initiates around the carbide precipitate at the grain boundary. Subsequently, Cr2 N precipitate lamellar gradually grows in the adjacent grain. The growth direction has a certain orientation relation with the austenitic crystal lattice.
出处
《金属热处理》
CAS
CSCD
北大核心
2016年第9期52-56,共5页
Heat Treatment of Metals
