Effects of V, Cr on transformation and deformation characteristics of Ti-50.8Ni superelastic alloy
Effects of V, Cr on transformation and deformation characteristics of Ti-50.8Ni superelastic alloy
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发表时间：
2007-12
影响因子：
2.3
通讯作者：
Zhi-rong He
中科院分区：
文献类型：
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作者：
Zhi-rong He
通过DSC和拉伸试验研究了V、Cr和退火温度对Ti-50.8Ni(原子分数,%)超弹性合金相变和变形特性的影响。 350—550℃退火合金在加热/冷却过程中发生两阶段可逆相变A■R■M（A—母相、R—R相、M—马氏体）。随着退火温度的升高，R、M相变温度θ_R和θ_M先升高后降低，M相变温度滞后Δθ_M不断减小，R相变温度滞后Δθ_R恒定。 0.5%V时,相变类型、Δθ_R和Δθ_M几乎没有变化,而θ_R和θ_M减小。添加0.3%Cr后,相变类型和Δθ_R几乎没有变化,但Δθ_M增大,θ_R和θ_M明显减小。400℃退火Ti-50.8Ni合金的超弹性应力和应变为473 MPa,添加0.3%Cr后，合金的超弹应力增加至620 MPa，超弹应变降低至3.5%。添加0.5%V后，超弹性应力和应变分别降低至388 MPa和4.9%。当退火温度从400℃升高到500℃时,三种合金的超弹应力均有所下降。
Effects of V,Cr and annealing temperature on transformation and deformation charac- teristics of Ti-50.8Ni(atomic fraction,%)superelastic alloy were investigated by DSC and tensile test. The two-stage reversible transformation A■R■M(A—parent phase,R—R phase,M—martensite) occurred during heating/cooling in 350—550℃annealed alloy.With increasing annealing temperature, the R and M transformation temperaturesθ_R andθ_M are first increasing and then decreasing;the M transformation temperature hysteresisΔθ_M decreases continuously;the R transformation temperature hysteresisΔθ_R is constant.After adding 0.5%V,the transformation type,Δθ_R andΔθ_M are nearly no change,while theθ_R andθ_M decrease.After adding 0.3%Cr,the transformation type andΔθ_R are nearly no change,but theΔθ_M increases,theθ_R andθ_M decrease obviously.The superelastic stress and strain of 400℃annealed Ti-50.8Ni alloy are 473 MPa and 6.4%,respectively.After adding 0.3%Cr the superelastic stress of the alloy increases to 620 MPa,and the superelastic strain decreases to 3.5%. After adding 0.5%V the superelastic stress and strain decrease to 388 MPa and 4.9%,respectively. When annealing temperature increased from 400℃to 500℃,the superelastic stresses of the three alloys all decrease.