时效温度对Ti-5523合金组织和性能的影响

Effects of aging temperature on microstructure and mechanical properties of Ti-5523 alloy

研究了不同时效温度对时效处理后的Ti-5523合金的微观组织和力学性能的影响。结果表明：在合金相变点（790±5）℃以下的760℃或相变点以上的840℃固溶处理1 h,460～580℃时效处理8 h,Ti-5523合金的微观组织和力学性能对时效温度敏感。合金强度随着时效温度升高而降低,塑性则逐渐提高。合金在760℃×1 h/AC固溶＋580℃×8 h/AC时效处理后的断后伸长率和断面收缩率分别为17. 50%和67%,具有良好的塑性。固溶及时效处理后的Ti-5523合金强度主要受α相含量和尺寸的影响,α相尺寸减小或α相含量增加均可以提高合金的强度。随着时效温度的升高,在双相区固溶的时效态合金的初α相逐渐从长条状向短球状、椭球状转变,且含有短球状、椭球状的初生α相的合金具有更好的塑性变形能力。由于初生α相和次生α相的尺寸、含量随着时效温度的增加而发生的改变对合金力学性能产生的影响是协同的,因此双相区固溶的时效态合金的力学性能对时效温度非常敏感。

Effects of aging temperature on microstructure and mechanical properties of the Ti-5523 titanium alloy were studied. The results show that the phase transformation point of the alloy is （790 ± 5） ℃; the microstructure and mechanical properties of the alloy are sensitive to aging temperature when solution treated below and above the phase transformation point （760 ℃ and 840 ℃,respectively） for 1 h and aged at 460 ~ 580 ℃ for 8 h. With the increase of aging temperature,the alloy strength decreases and the plasticity increases gradually.After 760 ℃ × 1 h/AC solution treatment and 580 ℃ × 8 h/AC aging,good plasticity can be obtained,the elongation and cross-sectional shrinkage of the alloy are 17. 50% and 67%,respectively. The strength of Ti-5523 alloy after solid solution and aging is mainly affected by the content and size of α phase,i. e.,the decrease of α phase size or the increase of α phase content can improve the strength of the alloy.The morphology of primary α phase of the alloy after solution treated in two-phase region is gradually changed from long strip to short spheroidicity and ellipsoid with the increase of the aging temperature,and the alloy with short spherical and ellipsoidal primary α phase exhibits better plastic deformation ability. The changes of the size and content of initial α phase and secondary α phase occur due to that the increase of the aging temperature exerts synergistic effects on the mechanical properties of the alloy. Thus,the mechanical properties of alloy solution treated in two regions are sensitive to aging temperature.