损伤容限型钛合金的等温锻造温度研究

研究了TC21钛合金在5.5×10-4s-1恒应变速率、40%变形程度条件下,等温锻造温度变化对锻件组织和性能的影响。结果表明:TC21钛合金显微组织对温度变化敏感,在两相区锻造时,显微组织由初生α相和β转变组织组成,并且随着变形温度的提高,初生等轴α相的含量逐渐减少,晶粒尺寸增大;在相变点温度锻造时得到网篮组织;在相变点以上温度锻造时得到片状组织。室温拉伸强度和断裂韧性随锻造温度的升高呈现增加趋势,室温拉伸塑性明显降低。在965℃等温锻造时,显微组织为较细的片状组织,强度、塑性和断裂韧性达到较佳匹配,获得较好的综合力学性能。965℃为较佳等温锻造温度。

Study on isothermal forging temperature of high damage-tolerant titanium alloy

The effect of isothermal forging temperature on microstructure and mechanical properties of TC21 alloy forg-ings was studied by isothermal forging at the strain rate of 5.5 × 10~(-4)s~(-1), deformation of 40％. The results show that the microstructure of TC21 is sensitive to forging temperature. The microstructure consists of primary a and transition β phase and when the alloy is deformed in α+β field, the volume fraction of primary equiaxed α decreases and its size increases with elevating temperature. Typical basketweave microstructure will be obtained when forging is made at the transition temperature, and the lamellar microstructure will be obtained in the β field. The tensile strength and fracture toughness are enhanced with elevating temperature, but the tensile ductility is reduced. When forging is made at 965℃, the thinner lamellar mierostructure will be obtained, which possesses a good match among strength, plasticity and fracture toughness. 965℃ is recommended for isothermal forging.