(北京有色金屬研究總院 有色金屬材料制備加工國家重點(diǎn)實(shí)驗(yàn)室，北京100088)
摘 要: 采用光學(xué)電鏡(OM)、掃描電鏡(SEM)、物相分析(XRD)以及透射電鏡(TEM)等手段，研究Mg-xGd-Zr(x=1%、2%、3%，摩爾分?jǐn)?shù))合金均勻化處理前后組織演變及方塊相的成分結(jié)構(gòu)。結(jié)果表明：方塊相為Gd2O3，均勻化處理前后其結(jié)構(gòu)皆為FCC，晶格常數(shù)a=0.53 nm。鑄態(tài)合金中Gd2O3數(shù)量較少且基本位于共晶組織附近，且隨著均勻化時(shí)間的延長，共晶組織回溶，Gd2O3數(shù)量明顯增多，且隨著合金中Gd含量的增高而顯著增加。在合金熔煉和凝固過程中生成了少量的Gd2O3，但大部分是在均勻化處理過程中晶界附近富Gd區(qū)氧化形成的。
關(guān)鍵字: Mg-xGd-Zr合金；均勻化；第二相；稀土
（State Key Laboratory for Non-ferrous Metals and Processes,
General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:The microstructure evolution of Mg-xGd-Zr(x=1%, 2%, 3%, mole fraction) alloys as well as the micro- structure of the cubic-shaped phase before and after homogenization were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and transmitted electron microscopy (TEM). The results show that the cubic-shaped phase is Gd2O3 and the structure is stable as FCC with the lattice constant a=0.53 nm before and after homogenization. Gd2O3 are enwrapped in the eutectic structure in the as-cast alloys, and the number increases obviously with increasing homogenization time. Furthermore, the number is proportional to the Gd content in the alloys. Gd2O3 nucleate and grow in the solidification process, whereas, mostly are formed in Gd-rich area near grain boundaries during the homogenization.
Key words: Mg-xGd-Zr alloy; homogenization; second phase; rare-earth
