热处理对β锻造Ti-22Al-25Nb合金组织和性能的影响
来源期刊：中国有色金属学报2010年第z1期(下册)
论文作者：梁晓波 程云君 张建伟 李世琼
文章页码：611 - 615
关键词：Ti2AlNb；金属间化合物；热处理；拉伸性能
Key words：Ti2AlNb; intermetallic compounds; heat treatment; tensile properties
摘 要：研究了β锻造的Ti-22Al-25Nb合金在固溶＋时效热处理过程中微观组织的转变规律，并对不同固溶温度＋800 ℃时效处理合金的室温和650 ℃拉伸性能进行了测试和分析。结果表明：合金经β锻造后的组织由少量α2颗粒、大量O相板条和B2相基体组成。在固溶处理过程中，组织中的O相板条发生溶解，数量减少，形状变短、变粗。在980 ℃以上固溶处理时，基体B2相发生明显的再结晶。固溶＋时效处理后，细小的二次O相板条再次从B2基体中析出，并最终形成一种具有短棒状或颗粒状的初生α2/O相＋细小的二次O相板条＋B2相基体组成的组织。随着微观组织中初生α2/O相数量的减少、二次O相板条数量增加，合金室温和650 ℃抗拉强度升高，伸长率降低。
Abstract: Microstructure evolution of the β-forged Ti-22Al-25Nb alloy during subsequent solution plus aging heat treatment was investigated. The tensile properties of the alloy with different heat treatments at room temperature and 650 ℃ were tested. It is found that after β-forging the microstructure is composed of a large number of O phase laths, a few a2 particles and B2 matrix. During solution treatment, the O phase lamellae in the microstructure solves, the volume fraction of O lamellae decreases, and the shape becomes short and coarse. The recrystallization of B2 matrix grains happens when the solution temperature is above 980 ℃. During aging treatment, the fine O phase lamellae precipitates from B2 matrix and the microstructure with the primary α2/O particles or short bar, the secondary fine O phase and the B2 matrix forms. The test results of the tensile properties exhibit that when the volume fraction of the primary α2/O particles decreases and that of the secondary fine O phase lamellae increases, the tensile strength of the alloys at RT and 650 ℃ rises and the RT ductility drops.
