CAJ | 학술논문

研究Ti-23A1-17Nbat%,下同)合金在不同热处理条件下形成的双态组织的微观细节特征及其形成规律,分析双态组织细节特征对力学性能的影响,探讨综合改善合金拉伸性能和高温持久性能的途径.结果表明,经α2+曰2两相区温度变形的该合金,通过固溶处理/连续冷却和固溶快冷+时效两种方式的热处理均可形成双态组织.其中固溶快冷+时效方式可以实现O相板条数量、尺寸、分布及排列更有效的控制,时效温度的降低有助于板条的细化和混乱排列.在α2相等轴颗粒形貌及体积分数基本一致(约15%～20%)的情况下,O相板条体积分数的增加有利于合金高温持久性能的显著提高,但会造成合金室温拉伸延伸率的下降;O相板条的细化有利于合金室温和高温拉伸性能的同时改善,但使高温持久性能有所降低;通过1060℃固溶处理/油淬+850℃时效处理获得的双态组织具有强度、塑性和高温长时性能的最好匹配.
연구Ti-23A1-17Nbat%,하동)합금재불동열처리조건하형성적쌍태조직적미관세절특정급기형성규률,분석쌍태조직세절특정대역학성능적영향,탐토종합개선합금랍신성능화고온지구성능적도경.결과표명,경α2+왈2량상구온도변형적해합금,통과고용처리/련속냉각화고용쾌랭+시효량충방식적열처리균가형성쌍태조직.기중고용쾌랭+시효방식가이실현O상판조수량、척촌、분포급배렬경유효적공제,시효온도적강저유조우판조적세화화혼란배렬.재α2상등축과립형모급체적분수기본일치(약15%～20%)적정황하,O상판조체적분수적증가유리우합금고온지구성능적현저제고,단회조성합금실온랍신연신솔적하강;O상판조적세화유리우합금실온화고온랍신성능적동시개선,단사고온지구성능유소강저;통과1060℃고용처리/유쉬+850℃시효처리획득적쌍태조직구유강도、소성화고온장시성능적최호필배.
The detailed microstructure characteristics and the formation regulation of the duplex microstructure of Ti-23Al-17Nb (at%) alloys under different heat treatment conditions were studied. The effects of detailed microstructure characteristics on the mechanical properties of alloys were also investigated. The approaches to improve the both tensile and endurance properties at elevated temperature were discussed. The results indicate that for the alloys forged in (α2+B2) phase field, the duplex microstructure can be obtained either by treatment of solution in (α2+B2) field and oil quenching plus aging in (α2+B2+0) field. The volume fraction, size and distribution pattern of O phase laths can be controlled well. The relatively lower aging temperature is of benefit to form the finer and more random distribution of O phase laths. Increasing the volume fractions of O phase laths can improve the endurance properties at elevated temperature but decrease the room-temperature elongation in the case of similar sizes and same percent content (15%-20%) as equiaxed α2 particles, while the finer sizes of O phase laths can increase the tensile properties both at room and elevated temperatures, but decrease the endurance properties. The optimum matching of tensile strength, elongation and endurance properties of the alloys at elevated temperature can be obtained by the heat treatment of 1060 ℃ solution and oil quenching plus 850 ℃ aging.