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研究了近γ组织TiAl合金在温度为950℃～1075℃,应变速率为2×10-4s-1～8×10-5s-1的超塑性行为。结果表明,该合金在上述试验条件下表现出优越的超塑性,拉伸延伸率最高达到570%。在温度高于1000℃及应变速率不大于17×10-4s-1时,应变速率敏感指数均高于05,最大值接近08。该合金超塑性变形的表观激活能为302kJmol,超塑性变形机制被认为是晶内滑移协调晶界滑动。
The superplastic behavior of TiAl alloy with near-γ microstructure at a strain rate of 2 × 10-4s-1 to 8 × 10-5s-1 at 950 ℃ ~ 1075 ℃ was studied. The results show that the alloy exhibits superior superplasticity under the above experimental conditions with a tensile elongation of up to 570%. When the temperature is higher than 1000 ℃ and the strain rate is not more than 17 × 10-4s-1, the strain rate sensitivity index is higher than 05 and the maximum value is close to 08. The apparent activation energy of the superplastic deformation of the alloy is 302kJmol, and the superplastic deformation mechanism is considered to be the intracrystalline slip-coordinated grain boundary sliding.