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.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2011年第3期260-263,193-194,共4页
Special Casting & Nonferrous Alloys
