The Ti-8.5Cr-1.5Sn β Ti alloy with twinning induced plasticity (TWIP) effect was selected for the quasi-static tensile and Charpy impact tests at 298 K and 77 K to determine whether the strengthening and toughening strategy by TWIP effect can be extended to the cryogenic temperature. As the impact deformation temperature decreased from 298 K to 77 K, the Charpy impact toughness decreased obviously, even though a superior strength-ductility synergy was obtained under quasi-static tensile deformation at 77 K. Because the inhibition of deformation twins (DTs) activity under Charpy impact deformation at 77 K, together with the premature cracking along the formed twin boundaries (TBs), the density and width of the activated DTs were significantly reduced. Meanwhile, the secondary DTs and DTs also were restrained due to the width of primary DTs was too narrow. The above influencing factors resulted in the size of plastic deformation region at crack tip at 77 K was obviously smaller than that at 298 K. The crack preferentially initiated and propagated along primary TBs, and finally a low Charpy impact absorbed energy was displayed at 77 K.

中文翻译：

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加载模式和温度对TWIP β Ti合金变形行为的耦合效应：从优异的拉伸强度-延展性协同到低夏比冲击韧性

选择具有孪生诱导塑性（TWIP）效应的Ti-8.5Cr-1.5Sn β Ti合金进行298 K和77 K的准静态拉伸和夏比冲击试验，以确定TWIP效应强韧化策略是否可行。延伸至低温。随着冲击变形温度从 298 K 降低到 77 K，夏比冲击韧性明显下降，尽管在 77 K 的准静态拉伸变形下获得了优异的强度-延展性协同作用。在 77 K 的夏比冲击变形下，加上沿形成的孪晶界 (TB) 过早开裂，活化的 DT 的密度和宽度显着减小。同时，由于主DT的宽度太窄，次要DT和DT也受到限制。上述影响因素导致77 K时裂纹尖端塑性变形区域尺寸明显小于298 K时裂纹尖端塑性变形区域的尺寸，裂纹优先沿初生TB萌生和扩展，最终在77 K时表现出较低的夏比冲击吸收能。