采用拉伸试验，研究厂不同应变速率（10－5-10－1S-1）下温度对台体积分数为0．8％的TiB2、具有近全片层组织的Ti—47Al—2Mn－2Nb金属间化合物的屈服强度和延伸率的影响，得到合金韧脆转变温度随应变速率升高而升高的变化关系，确定这种含TiB2的TiAL合金的韧脆转变激活能为256kJ／mol这一数值低于无TiB2的合金的韧脆转变激活能（324kJ／mol），接近TiAl合金中原子自扩散激活能结合断口分析和理论计算结果，表明这种含TiB2的TiAl合金韧脆转变过程可能受位错攀移机制控制.
The effect of strain rate on the tensile yield strength and elongation of titanium aluminide has been studied. The alloy has a composition of Ti-47Al-2Mn-2Nb-0.8TiB2 (atomic fraction, %; volume fraction, %, only for TiB2) and near lamellar dricrostructure. It manifests brittle-to-ductile transition (BDT) at elevated temperature and its brittle-to-ductile transition temperature (TBDT) is positively sensitive to the strain rate. The addition of boron lowers the TBDT considerably, and the corresponding activation energy of BDT decreases to 256 kJ/mol, which is less than that of the alloy without boron (TiB2), but approximates the self-diffusion activation energy of atoms in the TiAl alloy. From additional fractography analysis and theoretical estimation, it is suggested that the BDT course of 7 titanium aluminide with the addition of boron (TiB2) is controlled by dislocation climbing.
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