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通过OM,XRD,TEM和SEM等手段研究了热处理前后Mg-10Gd-2.5Nd-0.5Zr(质量分数,%)合金的显微组织形貌,并在3.5%(质量分数)Na Cl溶液中进行了0~96 h的失重腐蚀实验。结果表明:合金铸态组织由α-Mg基体和粗大的枝晶β相组成,热处理后,合金中的β相经溶解再析出过程,由断续网状转变为方块颗粒状;在3.5%Na Cl溶液中,经热处理后,合金的耐蚀性能明显提高,其平均腐蚀速率由铸态时的0.74 mg·cm~(-2)·d~(-1),降低到固溶态时的0.41 mg·cm~(-2)·d~(-1)和时效态时的0.35 mg·cm~(-2)·d~(-1),且腐蚀产物以Mg(OH)2为主。
The microstructure of Mg-10Gd-2.5Nd-0.5Zr (mass fraction,%) alloy before and after heat treatment was studied by means of OM, XRD, TEM and SEM, and was carried out in 3.5% NaCl solution 0 ~ 96 h weightlessness corrosion test. The results show that the as-cast microstructure of the alloy consists of α-Mg matrix and coarse dendritic β phase. After heat treatment, the β phase in the alloy is dissolved and re-precipitated, Cl solution, the corrosion resistance of the alloy increases obviously after heat treatment, and the average corrosion rate decreases from 0.74 mg · cm -2 · d -1 at as-cast condition to 0.41 mg · cm -2 · d -1 and 0.35 mg · cm -2 · d -1 at aging, respectively, and the corrosion products were dominated by Mg (OH) 2.