泡沫铝半固态制备工艺及组织研究

Semi-solid Preparing Aluminum Foam and Its Microstructure

针对闭孔泡沫铝制备过程中孔结构控制问题,提出了一种基于半固态成形技术的两步法泡沫铝制备新工艺[即先用半固态成形技术制备预制体,再用二次加热发泡法(Semi-solid foaming)]-SSF法发泡。就SSF法的基本工艺参数对发泡过程和孔结构的影响以及工艺参数的优化等问题进行了研究。结果表明,SSF法可以控制TiH2的分解时间,实现二次发泡工艺,获得孔结构较均匀、孔隙率为74.6%、孔径范围为2.1～3.2mm(平均值为2.3mm)、平均圆度为0.812的泡沫铝硅合金。试验条件下的最佳工艺参数:搅拌温度为580℃,搅拌时间为0.5min,搅拌速度为1200r/min,二次发泡炉温为720℃,加热时间为15min。

Based on semi-solid forming technology,a two-step forming process for aluminum foam that is semi-solid foaming (SSF) was put forward to control the cell structure of closed-cell aluminum foam. Effects of basic processing parameters of SSF on foaming process and cell structure as well as its optimization were investigated. The results reveal that SSF can control decomposing time of TiH2,realizing secondary foaming process,and Al-Si aluminum foam with uniform cell structure in which cell porosity is 74.6% with cell diameters of 2.1~3.2 mm and average roundness of 0.812 can be obtained. The optimized processing parameters are as follows:stirring temperature of 580 ℃,stirring time of 0.5 min and stirring velocities of 1200 r/min,re-forming temperature of furnace of 720 ℃ and heating time of 15 min.