冷轧与退火对LA91合金显微组织和力学性能的影响

Effects of Cold Rolling and Annealing Treatment on Microstructure and Mechanical Properties of LA91 Alloy

对热挤压态LA91合金进行了冷轧及退火处理,研究了不同冷轧变形量与退火温度对合金显微组织和力学性能的影响。结果表明,总轧制变形量为76.7%的LA91合金薄板具有较高的强度和良好的塑性（抗拉强度为177 MPa,伸长率为37.4%）。在200~300℃范围内退火,冷轧LA91合金发生回复和再结晶,β相逐渐变为等轴状,α相逐渐球状化。因此,随退火温度升高,合金薄板的抗拉强度先降低后升高,伸长率则先升高后降低。同一变形量下,合金中的α相再结晶温度略高于β相;经1h退火,不同变形量的冷轧LA91合金开始再结晶的温度略微不同,约为250℃,退火温度为300℃时,再结晶完成。

A hot extruded LA91alloy was cold-rolled and then annealed,and effects of cold rolling and annealing temperature on microstructure and mechanical properties of LA91alloy were investigated.The results show that,the LA91alloy sheet with 76.7%rolling deformation exhibits high strength and excellent ductility（177MPa and 37.4%,respectively）.Annealing at range of 200 ℃~300 ℃,recovery and recrystallization of cold-rolled LA91alloy sheets occur,andβphase gradually become equiaxed, whileαphase gradually is spheroidized.Therefore,with the increase of annealing temperature,the tensile strength of sheets is decreased firstly and then increase with the increase of elongation first and then decrease.The recrystallization temperature ofαphase in the alloy is slightly higher thanβphase,with a fixed alloy deformation.The starting recrystallization temperature with different cold deformation rate is slightly different with annealing for 1h,and the recrystallization is completed at 300℃.