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研究了时效对一种新型Ti-6Cr-5Mo-5V-4Al合金组织与拉伸性能的影响。研究发现:Ti-6Cr-5Mo-5V-4Al合金在α/β固溶+时效处理后的典型组织为:β晶粒破碎,β晶界处有连续和不连续的项链状初生α相,晶内有不连续的球状初生α相及时效过程析出纵横交错的细小次生α相。β固溶+时效处理后的典型组织为:等轴β晶粒晶界处析出沿着一定取向的次生α相薄片层,晶内弥散分布着平行交错的细小次生α相;在本研究范围内,Ti-6Cr-5Mo-5V-4Al合金经β固溶+时效处理时,低于500℃长时间时效和高于500℃短时间时效有利于合金强化;α/β固溶+时效处理时,低于500℃短时间时效有利于合金强化,而高于500℃或长时间都会降低合金强度,而且在较宽的时效温度范围内都具有良好的强度塑性匹配。Ti-6Cr-5Mo-5V-4Al合金在低于500℃时效时,α/β固溶+时效处理的合金其强度塑性匹配优于β固溶+时效处理处理后的合金;高于500℃时效时,β固溶+时效处理后合金其强度塑性匹配优于α/β固溶+时效处理后的合金。另外,短时间直接时效可以迅速提高合金强度,同时保持优良的塑性,500℃/2h直接时效后强度达1590MPa,同时保持6.5%的延伸率。
The effect of aging on the tensile properties of a novel Ti-6Cr-5Mo-5V-4Al alloy was investigated. The results show that the typical microstructure of Ti-6Cr-5Mo-5V-4Al alloy after α / β solution treatment and aging is that the β grains are broken, the continuous and discontinuous neck-like primary α phase and crystal There are discontinuous spherical primary α phase and aging process precipitated fine secondary α phase criss-cross. The typical microstructure after β-solution treatment and aging treatment is as follows: the secondary α-phase lamellae precipitated along the grain boundaries of the equiaxed β grains with fine secondary α phase dispersed in parallel in the grain; Within the range of Ti-6Cr-5Mo-5V-4Al alloy by β solution + aging treatment, less than 500 ℃ aging time and more than 500 ℃ short time aging is conducive to alloy strengthening; α / β solution + aging treatment Aging at less than 500 ° C for a short period of time is beneficial for alloying and above 500 ° C or for a long period of time reduces the strength of the alloy and provides good strength plastic matching over a wide range of aging temperatures. When aging at less than 500 ℃, Ti-6Cr-5Mo-5V-4Al alloy has better strength-plastic matching than that of β-solution + aging treatment when aging at 500 ℃ , The strength and plasticity of alloy after β-solution treatment and aging treatment is better than α / β solution + aging treatment. In addition, direct aging for a short period of time can rapidly increase the strength of the alloy while maintaining excellent ductility, with a strength of 1590 MPa after direct aging at 500 ° C / 2h while maintaining a 6.5% elongation.