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研究了固溶、固溶时效、短时退火对Ti-18Nb-10Zr(at%)合金微观组织和超弹性的影响。采用室温拉伸测试了合金超弹性;借助X射线衍射(XRD)、电子背散射衍射(EBSD)、透射电子显微镜(TEM)对微观组织、相变行为进行了观察与分析。结果表明,冷轧态Ti-18Nb-10Zr合金,800℃固溶后,发生了完全再结晶,由β相和细小的无热ω相组成,回复应变约为2.65%;再在350℃时效后,由于等温ω相尺寸和体积分数显著增加,急剧降低了合金Ms,应力-应变曲线未呈现超弹性;650℃短时退火后,合金基本完成再结晶,由单一的β相组成,平均晶粒尺寸约为10μm,晶粒细化改善了合金超弹性,回复应变约为2.86%。
The effects of solution, solution and aging, and short-term annealing on the microstructure and superelasticity of Ti-18Nb-10Zr (at%) alloys were investigated. The superelasticity of the alloy was tested by tensile testing at room temperature. The microstructure and transformation behavior of the alloy were observed and analyzed by X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that the complete recrystallization of the as-cast Ti-18Nb-10Zr alloy after solution treatment at 800 ℃ is composed of β phase and fine non-thermal ω phase, and the recovery strain is about 2.65%. After aging at 350 ℃ , The as-quenched ω-phase phase size and volume fraction increase dramatically, and the alloy Ms decreases sharply. The stress-strain curve does not show hyperelasticity. After short annealing at 650 ℃, the alloy basically recrystallizes and consists of a single β phase. With a size of about 10μm, grain refinement improves the superelasticity of the alloy and the recovery strain is about 2.86%.