Zr-Cr-Y体系相平衡的实验测定和热力学计算

Experimental determination and thermodynamic assessment of the Zr-Cr-Y ternary system

采用关键实验和相图计算相结合的方法对Zr-Cr-Y体系的相平衡进行研究。采用熔炼法制备8种不同成分的Zr-Cr-Y合金,借助X射线衍射和扫描电镜对Zr-Cr-Y三元系的1000、900、800和600℃等温截面进行实验测定。结果表明,该体系存在BCC(Cr)+HCP(Y)+αCr_(2)Zr、BCC(Zr)+HCP(Y)+αCr_(2)Zr和HCP(Zr)+HCP(Y)+αCr_(2)Zr等3个三相区。根据本工作获得的相平衡数据,对Zr-Cr-Y三元系进行热力学建模,采用CALPHAD(calculation of phase diagrams)方法对该三元系进行热力学优化,获得一套能准确描述Zr-Cr-Y三元系的热力学参数。计算结果与实验数据吻合较好。

The phase equilibria of the Zr-Cr-Y system was investigated by combination of key experiments and CALPHAD(calculation of phase diagrams)methods.Eight ternary alloys were prepared to determine the isothermal sections of the Zr-Cr-Y system at 1000,900,800 and 600℃by means of X-ray diffraction(XRD)and scanning electron microscope with energy dispersive X-ray spectroscopy(SEM/EDS).The results show that there are three-phase regions,i.e.,BCC(Cr)+HCP(Y)+αCr_(2)Zr,BCC(Zr)+HCP(Y)+αCr_(2)Zr and HCP(Zr)+HCP(Y)+αCr_(2)Zr in this system.Based on the experimental equilibria data obtained in the present work,thermodynamic modeling of the Zr-Cr-Y ternary system was performed by the CALPHAD method.A set of accurate thermodynamic parameters of the Zr-Cr-Y system were obtained.The calculated results are in good agreement with most of the reliable experimental data.