内浇包熔体温度对7075/6009复合板材组织性能的影响

Effects of ladle inside melt temperature on microsturctures and properties of 7075/6009 composite plates

采用双流浇注连续铸造方法,通过改变内浇包熔体温度制备了7075/6009合金铸锭。重点研究了不同内浇包熔体温度下所制备的7075/6009铸锭经过自由压制和轧制变形后的组织和性能。结果表明:7075/6009合金板材在轧制和热处理状态下,当内浇包熔体浇注温度从680℃升高到780℃时,其抗拉强度、屈服强度都会提高,而伸长率变化较小,这主要是由于内浇包熔体温度升高,导致外层合金厚度减小,内层合金在复合材料中的体积分数增加。合金板材在T6热处理状态下获得的最优力学性能是:抗拉强度为404 MPa,屈服强度为364 MPa,伸长率为15.3%。

The ingots of 7075/6009 aluminum composites were prepared by adjusting the temperature of ladle inside melt from 680 ℃, 730 ℃to 780℃ in double-stream-pouring continuous casting. The ingots were then deformed by free hot compression and hot rolling. The effects of pouring temperatures of the melts inside ladles on macro- and micro-structure and tensile property of the 7075/6009 aluminum composite plates were studied. The results show that the tensile strength and yield strength of the rolled and heat-treated sheets increase, however, the elongation of the sheets has little change when the temperatures of the melt in inside ladle increase from 680 ℃ to 780 ℃. This occurrence is attributed to the decrease of the thickness of the external layer and the increase of the volume fraction of the internal 7075 alloy with the increase of the melt temperature inside ladle. The optimal tensile property of 7075/6009 aluminum composite plates under T6 condition is that the ultimate strength, yield stress and elongation are 404 MPa, 364 MPa and 15.3% respectively.