7050铝合金热变形程度对再结晶及其性能的影响

Influence of hot deformation degree on recrystallization and properties of aluminum alloy 7050

7050铝合金热变形过程中变形程度对再结晶有重要的影响,而其各项性能与再结晶程度有关。厚度为40 mm的7050铝合金板材在410℃,以1 mm·s^(-1)的速度分别压至25,20,15和10 mm。不同热变形程度的试样固溶、时效后,观察其金相组织、透射形貌,检测其硬度、电导率、室温拉伸、疲劳及晶间腐蚀性能等。实验结果表明,7050铝合金随着热压过程中变形程度的增加,再结晶程度逐渐上升。变形程度的增加使得再结晶晶粒增多,从而7050铝合金各项力学性能得到显著地提高,其中维氏硬度提高26 HV,屈服强度及抗拉强度分别提高36和51 MPa,疲劳断裂循环次数提高376万次,但抗腐蚀性能稍有下降。

The deformation degree of aluminum alloy 7050 in the hot deformation has important influence on recrystallization,and its properties relate to the degree of recrystallization. Then,aluminum alloy 7050 sheets with 40 mm thickness were pressed to 25,20,15 and 10 mm at 410 ℃,10 mm·s^（-1）. Furthermore,the microstructure,transmission topography,hardness,electrical conductivity,room temperature tensile properties,fatigue properties and intergranular corrosion properties of specimens with different thermal deformation degrees were investigated after solid solution and aging treatment. The experimental results show that the recrystallization increases gradually with the increase of the deformation degree during the hot compressing of aluminum alloy 7050. However,the increasing deformation degree increases the number of fine recrystallized grains,and the mechanical properties of aluminum alloy 7050 are remarkably improved as the Vickers hardness increases by 26 HV,the yield strength and tensile strength increase by 36 and 51 MPa respectively,and the number of fatigue fracture cycles increases by 3. 76 million times,but the corrosion resistance decreases slightly.