B、Y及冷却速度对Ti-47Al-2Cr-2Nb合金组织的细化作用  

Effects of minor B, Y and Cooling Rate on the Microstructure Refinement of Ti-47Al-2Cr-2Nb Alloy

作　　者：王建吉[1] 杨莉莉[1] 郑立静[1] 闫洁[1] 肖志霞[1] 李国强 张虎[1] 

机构地区：[1]北京航空航天大学材料科学与工程学院 [2]中国浦发机械工业股份有限公司经营管理部

出　　处：《特种铸造及有色合金》2011年第3期260-263,193-194,共4页Special Casting & Nonferrous Alloys

摘　　要：研究了微量元素B、Y和冷却速度对Ti-47Al-2Cr-2Nb合金组织的复合细化效果。结果表明,在水冷铜坩埚磁悬浮真空感应熔炼和Y2O3型壳精密铸造条件下,B元素能够有效细化Ti-47Al-2Cr-2Nb铸件的晶粒尺寸,使其由粗大的柱状晶变为细小的等轴晶组织,但没有起到细化片层间距的明显作用。B、Y复合细化可以在B元素细化效果的基础上进一步细化片层团尺寸,同时显著细化片层间距。在壁厚为2～20mm范围内,Ti-47Al-2Cr-2Nb-0.8B-0.3Y铸件的宏观组织均为等轴晶;且随着厚度的增加,等轴晶尺寸逐渐增大。适当降低型壳预热温度也有助于获得细小的片层组织。Effects of minor B and Y as well as cooling rate on compound refinement of microstructure of Ti+47Al-2Cr-2Nb alloy were investigated. The results show that in the condition of smelting with the water-cooled copper crucible vacuum induction skull furnace and investment casting with Y2O3 shell mold, grain size of Ti-47Al-2Cr-2Nb castings is greatly refined with B addition, where coarse columnar grain is converted into fine equaixed one, however, refining effects on lamellar spacing are absent. B and Y compound refinement can not only further effectively refine grain size, but also significantly refine the lamellar spacing. Macro-structure of Ti-47Al-2Cr-2Nb-0.8B-0.3Y alloy castings exhibits equiaxed grain with different thickness from 2 mm to 20 mm, meanwhile, with increasing in thickness of the castings, equiaxed grain size is gradually coarsened. It is beneficial for obtaining fine lamellar structure with proper decrease of pre-heating temperature of mold shell.

关 键 词：TIAL合金 晶粒尺寸 B元素 Y元素 冷却速度 

分 类 号：TG292[金属学及工艺—铸造]