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利用Hopkinson压杆装置,对Ti-5Mo-5V-2Cr-3Al(TB10)合金进行高速冲击试验,采用光学显微镜和透射电镜分析其冲击相变与动态承载能力之间的关系。结果表明,显微组织状态对绝热剪切敏感性影响很大,在相同的应变率条件下,两相区固溶+时效、两相区固溶+双重时效的TB10合金试样中均可观察到明显的绝热剪切带,且沿剪切带出现裂纹,而固溶态试样晶粒的变形是均匀的,没有观察到绝热剪切带,其相对于前两者是绝热剪切不敏感的组织状态;在高应变率下,固溶态的试样发生了应力诱发马氏体相变;β晶粒内的条状析出物是由β相和斜方马氏体相混合构成;由于相变过程吸收了一部分冲击功,使试样未能达到材料本构失稳形成ASB的临界条件,且应力诱发马氏体相具有较高的均匀伸长率及较大的塑性,使试样仍具有较好的动态承载能力。
The high-speed impact test of Ti-5Mo-5V-2Cr-3Al (TB10) alloy was carried out by using Hopkinson pressure bar device. The relationship between impact phase transformation and dynamic load-bearing capacity was analyzed by optical microscope and transmission electron microscope. The results show that the microstructure has a great influence on the adiabatic shear susceptibility. Under the same strain rate, both the solid solution + aging in two-phase zone, the solid solution in the two-phase zone + the double-aging TB10 alloy can be observed To the obvious adiabatic shear band and the crack along the shear band, while the deformation of the solid solution sample grains is uniform and no adiabatic shear band is observed, which is insensitive to adiabatic shear with respect to the former two At the high strain rate, the stress-induced martensitic transformation takes place in the solid-solution samples. The strip-like precipitates in the β-grains are formed by the mixture of β-phase and rhombic martensite. Due to The phase change process absorbs a part of the impact energy, so that the specimen fails to reach the critical condition of instability of material to form ASB, and the stress-induced martensite phase has a higher uniform elongation and larger plasticity, so that the sample Still have a good dynamic carrying capacity.