材料期刊网

碳化硅颗粒增强铝基复合材料具有优异的性能,在许多领域都备受青睐,然而焊接性较差,成为制约其广泛应用的瓶颈难题.本文采用搅拌摩擦焊的方法,实现了低体积分数SiCp/Al复合材料封装盒体的连接.试验中采用圆锥形WC-Co合金搅拌头,搅拌头轴肩直径为10 mm,锥头直径3 mm,锥尾直径5 mm,搅拌针高度2.5 mm,采用下压力控制方式,焊接工艺参数为:下压力控制在2 kN,搅拌头倾角为3°,搅拌头转速为1500 RPM,焊接速度保持在120 mm/min,下压深度为2.55 mm,能够获得表面及内部质量良好的焊接接头.经过搅拌摩擦焊后,搅拌区的碳化硅颗粒尺寸更加细小,分布也更加均匀,搅拌区中没有出现孔洞、沟槽等搅拌摩擦焊常见缺陷.热机影响区内部分布着大量严重变形的结构,这主要是由于母材组织被拉长后伴随着塑性流动而产生的较大变形.母材区的平均硬度值最高,为61.9 HV3,搅拌区的平均硬度为58.3 HV3,热机影响区的平均硬度最低,为55.4 HV3.

SiC particle reinforced aluminum metal matrix composites (SiCp/Al MMCs) has excellent properties, which is very promising in many fields.However, the poor weldability is the bottleneck problem for its wide application.Using friction stir welding (FSW), the packaging container made of SiCp/Al MMCs with low volume fraction was welded successfully in this paper.In this experiment, FSW-tool was a cone shaped wear resistant WC-Co tool with shoulder diameter of 10 mm, base cone diameter of 5 mm, cone tip diameter of 3 mm and cone height of 2.5 mm.Welded joint with good quality at both surface and internal could be obtained under the optimal process parameters: pressing force 2 kN (force controlled), tool tilt angle of 3°, spindle speed of 1500 RPM, transitional speed 120 mm/min and plunge depth of 2.55 mm.After FSW processing,SiC size in stir zone became smaller and its distribution in this area was more homogeneous.Moreover, the common defect in FSW joint such as hole, groove were free from in the stir zone.A large number of distorted structures in thermal-mechanical affected zone can be found.This is mainly due to the elongation of base metal structure and then followed by plastic flow.The highest average hardness value in base metal is 61.9 HV3.The average hardness in stir zone is 58.3 HV3.The lowest average hardness value in thermal-mechanical affected zone is 55.4 HV3.