抄録
The precipitation behavior during homogenization of DC cast aluminum alloy 1100 has been invesigated by means of electrical resistivity measurement and transmission electron microscopy. Precipitation is accelerated above 300°C and small AlFeSi precipitates (mainly of α-AlFeSi) are observed around 450°C, when ingot is heated up at a rate of 50°C/hr. The precipitates grow and disperse in matrix along with dissolution of α-AlFeSi, precipitation of Al3Fe and probable transformation from α to Al3Fe, when heated above 500°C or held at each temperature. Al3Fe also precipitates at the interface between crystallized intermetallic compound and matrix above 550°C, and no precipitates exist in the matrix after prolonged holding at 600°C. In case where the ingot is cooled down at 20°C/hr and held after homogenization at 550°C the 3hr, precipitation progresses with almost constant distribution in matrix. The precipitates appear in matrix at lower temperature around 400°C and after prolonged holding below 500°C, when the ingots are cooled after heating at 600°C for 9hr.
