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在含1.0%Fe的A356铝合金中加入1.2%的Mn,经850℃熔化后降至615~680℃保温1小时。采用OM、SEM、EDS等研究手段研究保温温度对富铁相沉降效率及机理的影响。研究结果表明,随着保温温度的降低,再生铝中含铁相逐渐降低,615℃时除铁率可达46.7%;基体中初生铁相随温度的降低由星形演变成多边形,615℃时初生富铁相基本消失。而炉渣则为规则的多边形,圆整度达到0.86;炉渣中及660℃保温时初生富铁相的Mn/Fe原子比较其余保温温度下基体中初生铁相大,达到1.70;不同保温温度下,富铁相的沉降过程分为4个阶段,前3个阶段影响富铁相沉降效率的最大因素分别为:富铁相形态、富铁相尺寸、富铁相密度。
1.2% Mn was added to the A356 aluminum alloy containing 1.0% Fe, melted at 850 ° C and then cooled to 615-680 ° C for 1 hour. The effects of holding temperature on the sedimentation efficiency and mechanism of iron-rich phase were studied by OM, SEM and EDS. The results show that with the decreasing of holding temperature, the content of iron in reclaimed aluminum gradually decreases and the iron removal rate reaches 46.7% at 615 ℃. The initial iron phase in the matrix evolves from star to polygon with the decrease of temperature. When the temperature is 615 ℃ Iron rich primary phase disappeared. While the slag is a regular polygon with a roundness of 0.86. The Mn / Fe atomic ratio of the primary iron-rich phase in the slag and the insulation at 660 ℃ is 1.70 higher than that in the rest of the matrix, reaching 1.70. Under different holding temperatures, The sedimentation process of iron-rich phase is divided into four stages. The most significant factors affecting the sedimentation efficiency of the iron-rich phase in the first three stages are the morphology of iron-rich phase, the size of iron-rich phase and the density of iron-rich phase.