等轴和片层组织Ti-55511合金热轧及退火过程中的组织演变及力学性能

Microstructure Evolution and Mechanical Properties of Ti-55511 Alloy with Equiaxed and Lamellar Microstructures During Hot Rolling and Annealing

摘要:

锻态Ti-55511合金经过不同的热处理工艺，获得等轴和片层2种初始组织。采用SEM、EBSD、TEM和拉伸试验研究了等轴和片层Ti-55511合金在热轧和退火过程中的组织演变和力学性能。结果表明：经750 ℃轧制，等轴组织中的α相轻微变形，β相发生动态回复和动态再结晶；而片层组织中的α相几乎平行分布，有些部分破碎，β相仅产生动态回复。等轴组织中的α相织构强度略有增加，片层组织中α相织构强度显著增加；而等轴和片层组织中β相织构强度均降低。同时，等轴组织力学性能各向异性很小，片层组织各向异性明显。600 ℃退火后，片层组织的α和β相织构强度均降低，力学性能的各向异性显著降低。

Abstract:

The equiaxed and lamellar microstructures of T-55511 alloy were obtained by different heat treatment routes. Microstructure evolution and mechanical properties of Ti-55511 alloy with equiaxed and lamellar microstructures during hot rolling and annealing were investigated by SEM, EBSD, TEM and tensile tests. The results show that equiaxed α phases are slightly deformed and β phase experiences dynamic recovery and dynamic recrystallization during 750 oC rolling; whereas lamellar α phase is nearly distributed in parallel, some of which are partly fragmentized, and β phase merely undergoes dynamic recovery. Texture intensity of α phase increases remarkably in lamellar structure but slightly in equiaxed structure, while texture intensity of β phase decreases both in equiaxed and lamellar structure. In addition, the anisotropy of equiaxed structure is small while that of lamellar structure is obvious. When the rolled lamellar structure is annealed at 600 °C, texture intensities of α and β phase both decrease and the anisotropy of mechanical properties significantly decreases.