固溶处理对Ni-Cr-W合金碳化物的影响

采用SEM、TEM和XRD等测试方法，研究了一种Ni-Cr-W合金经不同温度（1230~1300 ℃）和不同时间（10~120 min）固溶处理后的显微组织。结果表明：经过固溶处理后，合金的析出相为富W的面心立方M6C和富Cr面心立方的M23C6。随着固溶温度升高和保温时间延长，碳化物体积分数降低。在1270 ℃, 120 min时，大部分的碳化物溶解进入基体，孪晶处的碳化物首先发生溶解。M6C与基体不存在任何位向关系，晶界上析出的M23C6(220)晶面与基体(11)晶面的夹角为30°。

Effects of Solution Heat Treatment on Carbide of Ni-Cr-W Superalloy

The microstructure features of a kind of Ni-Cr-W superalloy after solution heat treatment at different temperatures (1230-1300 °C) for various time (10-120 min) were investigated by means of scanning electron microscope (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results show that the precipitated phases of the alloy after solution heat treatment are identified as W-rich fcc M6C and Cr-rich fcc M23C6 carbides. The volume fraction of carbides decreases with increasing of the solution heat treatment temperature and time. At the temperature above 1270 °C for 120 min, most of carbides are dissolved into the Ni-matrix, and the carbides distributing at twin boundaries may be dissolved into the matrix first. M6C carbide has no any fixed orientation relationship with the Ni-matrix, but the angle of M23C6 (220) to the matrix (11) is 30°.