T45Al10Nb附带 金全片层组织韧脆转变机制的研究

Effect of Strain Rate on Brittle-Ductile Transition Mechanism of the Ti45Al10Nb Alloy with Fully Lamellar Microstructure

摘要:

研究了应变速率和温度对Ｔｉ４５Ａｌ１０Ｎｂ合金的屈服强度和延伸率的影响。结果表明：随着应经升高，合金的屈服强度升高而延伸率下降，由此得到韧脆温度ＴＢＤＴ随应变束率升高而升工计算出Ｔｉ４５Ａｌ１０Ｎｂ合金韧脆转变的激活能为３３０ＫＪ／ｍｏｌ。这一数值与ｒ－ＴｉＡｌ合金中原子的自扩散激活能（２９０ＫＪ／ｍｏｌ）相当，说明Ｔｉ４５Ａｌ１０Ｎｂ合金韧脆转变过程受扩散控制的形迹机制，即位错攀移控制，ＴＥＭ形

Abstract:

The effects of strain rate and temperature on the tensile yield strength and elongation of titanium aluminides are studied. The alloy Ti 45Al 10Nb(at%) has a fully lamellar microstructure. The test results show that the brittle ductile transition(BDT) temperature increases with the increases of strain rate and temperature. The activation energy is 330kJ/mol, which approximates to the self diffusion activation energy of atoms in the TiAl alloy. Fractography and dislocation configuration analyses demonstrate that the brittle ductile transition of the alloy Ti 45Al 10Nb is controlled by dislocation climb.