固溶时间对7050航空铝合金锻件组织和性能的影响

Influence of solid solution time on microstructure and properties of 7050 aerial aluminum alloy forgings

通过差热分析(DSC)、室温拉伸、断裂力学实验、扫描电子显微镜(SEM)和能谱分析等方法,研究了固溶时间对7050航空铝合金锻件力学性能、断口形貌和断裂韧性等的影响。结果表明:当固溶时间小于90 min时,随着固溶时间的增加,合金中第二相粒子逐渐溶入基体,残余粗大的第二相粒子主要是Al2Cu Mg和Al7Cu2Fe相;当固溶时间为90 min时,7050铝合金锻件的抗拉强度、屈服强度和断裂韧性分别达到最大值530 MPa、490 MPa和37. 7 MPa·m1/2。7050铝合金的断裂方式主要是延性断裂中的滑移分离断裂;在固溶时间30～90 min区间,随着固溶时间的增加,韧窝的尺寸、数量和深度逐渐增大;继续增加固溶时间,韧窝的数量减少,深度也逐渐变浅。7050航空铝合金锻件的最佳固溶处理制度为475℃×90 min。

The influences of solid solution time on mechanical properties,fracture morphology and fracture toughness of 7050 aerial aluminum alloy forgings were studied by differential scanning calorimetry(DSC),tensile at room temperature,fracture mechanics experiment,scanning electron microscopy(SEM)and energy spectrum analysis.The results show that when the solid solution time is less than 90 min,with the increase of solid solution time,the second phase particles in the alloy dissolve into the matrix gradually,and the remaining coarse second phase particles are mainly Al2CuMg and Al7Cu2Fe phases.When the solid solution time is 90 min,the tensile strength,yield strength and fracture toughness of 7050 aluminum alloy forgings reach the maximum value of 530 MPa,490 MPa and 37.7 MPa·m^1/2,respectively,and the fracture mode of 7050 aluminum alloy is mainly the slip-separation fracture in ductile fracture.When the solid solution time is between 30-90 min,with the increase of solid solution time,the size,number and depth of the dimple increase.However,if the solid solution time increases continuously,the number and depth of dimples decrease gradually.Thus,the optimal solid solution treatment for 7050 aerial aluminum alloy forging is 475℃×90 min.