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采用光学显微镜、扫描电镜、单向拉伸、硬度等分析检测手段,研究固溶温度(490~590℃)对6181A铝合金轧制板材的显微组织、力学性能以及腐蚀性能的影响规律。结果表明:合金的强度随固溶温度升高呈先升高后下降的趋势,550℃时达到最高值。在此条件下,合金的抗拉强度和屈服强度分别为373 MPa和335 MPa。固溶处理后残余的可溶第二相粒子和再结晶程度是影响拉伸断口形貌的主要因素。温度小于530℃时,合金的断裂为包含第二相粒子的韧窝型断裂。温度大于530℃时,合金的断裂为晶内韧性断裂与沿晶断裂的混合型断裂。晶间腐蚀的最大深度随固溶温度升高呈现先增加后降低的趋势。固溶温度影响晶界第二相析出状态及晶粒的大小,进而影响腐蚀速率和腐蚀扩展路径,两种因素共同决定合金最大腐蚀深度。
The effects of solution temperature (490 ~ 590 ℃) on the microstructure, mechanical properties and corrosion resistance of 6181A aluminum alloy rolled sheet were studied by means of optical microscope, scanning electron microscope, uniaxial stretching and hardness testing. The results show that the strength of the alloy first increases and then decreases with the increase of solution temperature, reaching the highest value at 550 ℃. Under these conditions, the tensile strength and yield strength of the alloy were 373 MPa and 335 MPa, respectively. The residual soluble second phase particles and degree of recrystallization after solution treatment are the main factors affecting the tensile fracture morphology. At temperatures below 530 ° C, the fracture of the alloy is a dimple-like fracture containing second phase particles. When the temperature is higher than 530 ℃, the fracture of the alloy is intracrystalline ductile fracture and intergranular fracture mixed fracture. The maximum depth of intergranular corrosion increases first and then decreases with the increase of solution temperature. The solution temperature affects the precipitation of the second phase and grain size in the grain boundary, which affects the corrosion rate and corrosion propagation path. Both factors determine the maximum corrosion depth of the alloy.