Effects of lanthanum on structures and grain sizes of Ti 44Al alloy

作     者：Liu Changming(刘昌明) Li Huaji(李华基) He Naijun(何乃军) 

作者机构：Chongqing Univ Sch Mech Engn State Key Lab Mech Transmiss Chongqing 400044 Peoples R China 

出 版 物：《中国有色金属学会会刊：英文版》 (Transactions of Nonferrous Metals Society of China)

年 卷 期：1999年第9卷第3期

页      面：599-604页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

主　　题：titanium alumiruium alloy lanthanum addition structures 

摘      要：By vacuum arc melting, lanthanum (La) was added in the range from 0.05% to 0.3% (mole fraction) to binary Ti 44%Al alloy to refine its fully lamellar (FL) colonies for high ductility. Effects of La on structures and grain sizes of the alloy were determined. It was observed that La greatly promoted growth of columnar grains in as cast structures of the ingots and reduced their diameters. The ingots were subsequently heat treated to obtain well defined fully lamellar structures. The material without La displayed large average size of equiaxed lamellar colonies over 1 400 μm (resulted from five measurement positions in a sample), and the material with 0.1% addition of La consisted of the finest average lamellar colonies as 381 μm, the finest grain size was 337 μm at top position. When La addition was over 0.1%, La stabilized the columnar structure and it was difficult to refine the columnar grains in heat treatment, therefore, grains were coarser.