Ll_0型TiAl金属间化合物的高温形变行为

HIGH TEMPERATURE DEFORMATION BEHAVIOUR OF TiAl INTERMETALLIC COMPOUND

研究了Ll_0型TiAl金属间化合物的高温压缩变形行为及再结晶组织,结果表明,与该化合物的单晶一样,多晶体的压缩屈服应力σ_(0.2)也具有正的温度依存性。流变应力与变形温度、应变速率之间较好地符合ε=A·σ_p^nexp(-Q/RT)关系。控制变形温度和应变速率,使合金的流变应力小于脆断应力时,不仅可以顺利实现TiAl基合金的高温塑性加工,而且在形变量合适时,可以获得晶粒明显细化的再结晶组织。

The behaviour of TiAl intermetallic compound of Ll_0 type under com-pressive deformation at high temperature and its recrystallization microstructurehave been studied. The compressive proof stress of the polycrystalline TiAl wasfound to be a positive temperature dependence as same as the single crystal one.The correlation of the flow stress together with strain rate and deformation tem-perature is in good agreement with the expression: ε=Aσ_p^nexp(-Q/RT)Adjusting the deformation temperature and strain rate to a decrease in flow stressof alloy down to below its brittle fracture stress may improve successfully notonly the hot working of the TiAl-base alloy but also the fineness of the recry-stalline grains.