7A09铝合金外筒零件开裂失效分析  

Failure analysis on cracking of 7A09 aluminum alloy outer cylinder parts

作　　者：王浩 付能 冯抗屯 Wang Hao;Fu Neng;Feng Kangtun(Aviation Industry Corporation of China Landing Gear Advanced Manufacturing Corporation,Changsha Hunan 410200,China)

机构地区：[1]中航飞机起落架有限责任公司,湖南长沙410200

出　　处：《金属热处理》2023年第5期298-302,共5页Heat Treatment of Metals

摘　　要：针对某飞机起落架7A09铝合金外筒在机械加工过程中出现多件开裂的情况,通过ICP光谱仪、拉伸试验机、扫描电镜、光学显微镜和能谱仪等对铝合金外筒化学成分、力学性能、微观断口形貌、显微组织和显微硬度进行了分析,探究7A09铝合金外筒裂纹的形成原因及机理。结果表明,7A09铝合金外筒的裂纹是由锻造高温下形成的初始裂纹源,在后续镗孔机加和热处理过程中产生的加工应力和热应力作用下,沿分模面过烧组织开裂成目视可见的纵向裂纹;裂纹形成的主要原因可能与锻造过程中分模面局部温度过高导致的组织过烧有关,属于锻造工艺缺陷。Several 7A09 aluminum alloy outer cylinders of aircraft landing gear were found cracked during machining.The chemical composition,mechanical properties,fracture micromorphology,microstructure and microhardness of the aluminum alloy outer cylinder were analyzed to investigate the essence and causes of the cracks by means of ICP spectrometer,tensile testing machine,scanning electron microscope,optical microscope and energy dispersive spectrometer.The results show that the crack of the 7A09 aluminum alloy outer cylinder is developed from the initial crack source formed by forging at high temperature,and then the overburning microstructure along the parting surface is cracked into visible longitudinal cracks under the interaction of machining stress and thermal stress generated during the subsequent boring and heat treatment process.The main reason for the crack formation may be related to the overburning of the microstructure caused by the excessively high local temperature of the parting surface during the forging process,which belongs to the forging process defect.

关 键 词：7A09铝合金 裂纹 失效分析 锻造工艺缺陷 过烧 

分 类 号：TG146.21[一般工业技术—材料科学与工程]