Ti-Nb-Zr-O高弹性钛合金自阻加热热处理过程组织演化及性能研究

Microstructure Evolution and Properties of Ti-Nb-Zr-O High Elastic Titanium Alloy during Self-resistance Heating Treatment Process

高弹性钛合金薄壁件等温热成形存在高弹性损失的性能缺陷。本研究以一种新型Ti-35Nb-2Zr-0.3O(Ti3523)高弹性钛合金为对象,比较了快速电阻加热和传统马弗炉加热对其微观组织和力学性能的影响,利用微观EBSD分析其弹性模量与屈服强度的影响机制。结果表明:较快加热速率下(约45℃/s)的快速电阻加热固溶处理明显抑制晶粒粗化,位错湮灭较少,空冷后的屈服强度相较于原始冷轧板坯下降约33.3%,明显优于马弗炉固溶处理,同时马氏体α′′相变趋势更高,弹性模量更低。时效处理后,快速电阻加热样品析出高强度α相,屈服强度与弹性模量均有所提高,其弹性性能(Ur=4.056)明显高于马弗炉加热样品(Ur=3.333),接近原始板坯(Ur=4.577)。本研究提出的快速加热高温成形方法为新型航空航天装备提供了一种可行技术路线。

The performance defect of high elastic loss exists in isothermal hot forming of thin-walled parts manufactured of high elastic titanium alloy.In this study,a new type of Ti-35Nb-2Zr-0.3O(Ti3523)high elastic titanium alloy was taken as the research object.The effects of solid solution and subsequent aging treatment under different heating methods on the microstructure and mechanical properties evolution of high elastic titanium alloy were investigated using rapid resistance heating and traditional muffle furnace heating.The influence mechanism of elastic modulus and yield strength was analyzed by microscopic EBSD.The results show that rapid resistance heating solution treatment at a faster heating rate(about 45℃/s)significantly inhibits grain coarsening and reduces dislocation annihilation.The yield strength after air cooling decreased by about 33.3%compared to the original cold-rolled sheet,which is significantly better than muffle furnace solution treatment.Meanwhile,the martensitic transformation trend is higher,and the elastic modulus is lower.After aging treatment,the rapid resistance heating speciment precipitated high-strengthαphase,and both yield strength and elastic modulus were increased.Its elastic performance(Ur=4.056)is significantly higher than that of muffle furnace heating speciment(Ur=3.333),approaching that of the original sheet(Ur=4.577).The rapid heating high temperature forming method proposed in this study provides a feasible technical route for new aerospace equipment.