摘要
采用端部淬火熄灭法分析了蔓延式燃烧合成Ｔｉ－５０ａｔ％Ａｌ合金中的组织结构转变动力学过程，发现合成反应从铝粉熔化处开始，合成反应表现为Ｔｉ＋Ａｌ→１／３ＴｉＡｌ３＋２／３Ｔｉ→ＴｉｘＡｌ＋（１－ｘ）Ｔｉ→ＴｉＡｌ等一系列过渡反应过程，这些反应的前期是可依靠液态反应物流动铺展进行质量传递的快速液－固型反应，可使试样温度迅速升高，为后续固－固型反应奠定良好扩散条件．由于扩散质量传递速度明显低于液相流动铺展，合成后期固－固反应速度较慢，在较快降温等条件下合成反应不能彻底完成，合金中将残留一部分未反应Ｔｉ芯，在反应后的冷却中，这些Ｔｉ芯表层含铝量较高部分可转化为α２－Ｔｉ３Ａｌ相，形成在Ｔｉ芯和ＴｉＡｌ产物间分布环状α２－Ｔｉ３Ａｌ相的特有组织结构．
The kinetics of microstructural transformation has been
analyzed using an endquenching and extinguishing method for a Ti50at%Al alloy synthesized
by combustion. It is shown that from start of aluminum powder melting, a series of transition
reactions takes place one after another as follows: Ti+Al1/3TiAl3+2/3TiTixAl+(1-x)TiTiAl. The
liquidsolid reaction at the early stage may heat the sample quickly, which can create a good
condition for later solidsolid reactions. Since masstransfer during solidstate diffusion is much
slower than that within liquid reactants, the later solidsolid reactions slow and some Ti core is
left in the alloy for rapid cooling. The aluminum contents of the boundary layers of the Ti cores
are higher than those of central parts of the Ti cores, and the boundary layers transform into
annular 2Ti3Al phase during cooling.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
1999年第3期161-165,共5页
Rare Metal Materials and Engineering
关键词
TIAL合金
燃烧合成
淬熄法
结构转变动力学
TiAl alloy, combustion synthesis,
microstructure, kinetics, masstransfer
