SP700钛合金板轧制过程的组织演变和力学性能研究

Research of Microstructure Evolution and Mechanical Properties of SP700 Titanium Alloy Sheet

研究了22mm厚SP700钛合金板轧制过程中的组织演变和力学性能。结果表明:SP700钛合金板的显微组织由不连续的晶界α相和晶内针状组织组成;经过热轧和冷轧后,显微组织不均匀,由等轴组织和变形组织组成,等轴组织由等轴α相和等轴β相组成,变形组织由条状α相和变形β相组成;冷轧并退火后,显微组织十分均匀,由等轴组织组成。室温拉伸试验结果表明:SP700钛合金板冷轧后,抗拉强度达1100MPa以上,纵横向强度差为64MPa,伸长率为5.0%~6.5%,塑性差为0.17%。退火后,强度降低,塑性显著提高;纵横向强度差为69MPa,塑性差为6.84%。

The microstructure evolution and mechanical properties of the 22 mm-thick SP700 titanium alloy sheet during rolling were studied.The results show that the microstructure of the SP700 titanium alloy sheet is composed of discontinuousαphase in the grain boundaries and acicular structure in the grains.The microstructure becomes inhomogeneous after hot rolling,which is composed of equiaxed microstructure and deformed microstructure.The equiaxed microstructure consists of equiaxedαandβphase.The deformed microstructure consists of stripedαphase and deformedβphase.After cold rolling and annealing,the microstructures are very uniform and consist of equiaxed microstructures.The tensile test at room temperature indicates that the cold-rolled SP700 titanium alloy sheet shows a tensile strength above 1 100 MPa with the difference between longitudinal strength and transverse strength of 63.67 MPa and an elongation of 5.0%-6.5%with the plastic difference of 0.17%.After annealing,the strength is decreased,and the elongation is increased significantly.The difference between longitudinal strength and transverse strength is 69 MPa,and the plastic difference is 6.84%.