相变条件对TB8钛合金显微组织及剪切性能的影响(英文)

Effect of Phase Transformation Conditions on the Microstructure and Shear Performance of TB8 Titanium Alloy

研究了TB8钛合金在不同热处理条件下的组织转变规律,并通过剪切实验分析了显微组织差异对于该合金剪切行为的影响。结果表明,热处理条件会影响TB8钛合金的显微组织,也会影响剪切变形行为。随着固溶处理温度升高,合金的晶粒明显变大,析出物的形貌也发生变化,剪切变形变得困难。固溶处理之后的时效温度对合金的剪切变形行为也有显著影响,在840℃固溶处理1 h之后,如果接着进行450℃/8 h时效处理,合金剪切变形所需的驱动力会降低;如果把时效热处理的温度提高到550℃,甚至更高(保温时间不变),那么剪切变形就会发生穿晶断裂。根据剪切检测结果可知,合金经过840℃/1 h固溶处理接着再进行500℃/8 h的时效处理可以获得优异的剪切性能,而且具有合理的显微组织。

Phase transformation of TB8 titanium alloy was studied under different heat treatment conditions; the effects of microstructure and phase composition on shear performance were investigated by microstructure characterization and fracture analysis. Results show that the heat treatment condition will affect the microstructure of TB8 titanium alloy, and also affect the shearing deformation behavior. With increasing of solution temperature, the size of grains increases obviously, the morphology of the precipitates also changes, and the starting of shearing deformation becomes difficult. The subsequent aging temperature after solution treatment will obviously influence the shearing deformation behavior of the alloy. After solution at 840 °C for 1 h followed by aging at 450 °C for 8 h, the driving force required for shear deformation will be decreased; when the subsequent aging temperature increases to 550 °C or more, shear fracture cut through grains. According to the results of shear tests, the alloy solutioned at 840 °C for 1 h followed by 500 °C/8 h aging can achieve an excellent shear performance with a reasonable microstructure.