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制备了细等轴、粗等轴、网篮三种不同初始组织的Ti-6Al-7Nb棒坯,研究了固溶温度、时效温度和时间对Ti-6Al-7Nb钛合金的性能及显微组织的影响。结果表明,试样强度随固溶温度的升高而升高,但超过相变点后,强度有所下降,而塑性则随固溶温度升高明显降低。随时效温度升高,等轴α相尺寸大大增大,含量基本无变化,在550℃时效的样品获得了最大的强化效果。在相同的时效温度(600℃)下,延长时效时间抗拉强度明显提高,但屈服强度基本保持稳定,塑性有恶化趋势。通过热处理形成的等轴α相有利于提高塑性指标,形成的次生条状α相有利于提高强度指标。在本研究中,具有等轴初始组织的棒坯最佳热处理制度为:940℃×1 h,AC+550℃×4 h,AC;网篮初始组织的试样还需要通过其他方法进一步提高塑性。
The Ti-6Al-7Nb billets with three different initial structures such as fine equiaxial, rough equiaxed and net basket were prepared. The effects of solution temperature, aging temperature and time on the properties and microstructure of Ti-6Al-7Nb titanium alloy Impact. The results show that the strength of the sample increases with the increase of the solution temperature, but the strength decreases slightly after the transformation temperature is exceeded, while the plasticity decreases with the increase of the solution temperature. As the aging temperature increases, the size of the equiaxed alpha phase increases greatly, and the content of the alpha-phase increases little, and the sample aged at 550 DEG C obtains the maximum strengthening effect. At the same aging temperature (600 ℃), the tensile strength of the extended aging time obviously increased, but the yield strength remained stable and the plastic tended to deteriorate. The equiaxed α phase formed by heat treatment is helpful to improve the plasticity index, and the formed secondary α-phase strip is helpful to improve the strength index. In the present study, the optimal heat treatment regime for the billet with an isometric initial structure is: 940 ° C for 1 h, AC + 550 ° C for 4 h, AC; and the initial sample of the basket also needs to be further improved by other methods .