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研究了AA6156铝合金在不同时效状态下的拉伸性能和平面应力断裂韧性。结果表明:AA6156合金薄板在自然时效态下断裂韧性最好,但强度偏低;在190℃单级峰时效和175℃/6 h+190℃/13 h双级过时效态下强度较好,但断裂韧性偏低;而在175℃/2 h+200℃/0.5 h双级时效态下达到较理想的强韧性匹配。由透射电镜和扫描电镜观察其微观组织及断口形貌得出:双级时效时,第一级预时效处理能增大GP区的析出数量,从而在后续第二级时效时极大地促进β″相更密集、更均匀地析出。时效制度对AA6156合金断裂韧性的影响主要取决于晶内析出相β″,而受晶界微观组织结构的影响较小。
The tensile properties and plane stress fracture toughness of AA6156 aluminum alloy under different aging conditions were studied. The results show that the fracture toughness of AA6156 alloy sheet is the best under natural aging condition, but its strength is low. The strength of AA6156 sheet is better under single-stage peak aging at 190 ℃ and double-stage over-aging at 175 ℃ / 6 h and 190 ℃ / 13 h, But the fracture toughness is low; however, the ideal toughness matching is achieved under the two-stage aging of 175 ℃ / 2 h + 200 ℃ / 0.5 h. The microstructure and fracture morphology observed by transmission electron microscopy and scanning electron microscopy show that the first-stage pre-aging treatment can increase the amount of precipitation in the GP region during the second-stage aging and greatly promote the β “ More dense and more precipitation.Aging system on the AA6156 alloy fracture toughness mainly depends on the intragranular precipitation phase β ”, but by the grain boundary microstructure less affected.