CT20钛合金挤压管坯冷轧过程中的组织演化

摘要

φ85 mm ×2.5 mm CT20 alloy tube blank was produced by using sheathed extrusion, two pass cogging rolling and single pass finishing rolling technique.The microstructure and room temperature tensile properties after deformation were observed in the tube of each processing.The microstructural evolution of the extrusion CT20 alloy tube blank during all processings was established.The results show that the CT20 alloy billet pierced in the βfield give a fine basket-weave structure.The 70% or higher processing deformation degree have fragmented the basket-weave structure in the billet, and the final microstructure of the tubes is the equiaxed α-grains.%采用包套挤压方式制备CT20钛合金管坯，经两道次两辊开坯轧制和一道次多辊精轧获得φ85 mm ×2.5 mm成品管材。研究了开坯、精轧一系列冷轧变形过程中的组织形态和室温力学性能变化，建立了挤压管坯加工过程的组织演变模型。结果表明：挤压制备的CT20钛合金管坯，其组织为细小均匀的网篮组织；对CT20钛合管坯进行大变形率（ε总＝70％）的两辊开坯轧制，能够获得细晶组织；多辊精轧管材加工态组织与上道次冷轧态组织相比变化不大，经900℃退火后形成均匀的等轴组织。