旋转速度对（WC+B4C）p/6063Al复合材料搅拌摩擦焊接头力学性能和微观组织的影响

搅拌摩擦焊的旋转速度对接头焊缝形貌、微观组织和力学性能均有较大的影响。采用搅拌摩擦焊方法对5 mm厚的(WC+B4C)p/6063Al复合材料进行焊接试验,固定焊接速度为100 mm.min-1,旋转速度分别为900,1100,1300和1500 r.min-1,焊后观察焊缝宏观形貌和各种缺陷,并对接头的微观组织和力学性能进行了分析。焊缝宏观缺陷研究结果表明,随着旋转速度的升高,焊接热输入量增大,金属流动性得到改善,飞边、沟槽等宏观缺陷显著增多,焊缝形貌越来越粗糙;接头微观组织研究表明,由于搅拌头的搅拌作用,相比于母材,在焊核区增强相颗粒分布更加均匀,更多增强相颗粒发生破碎,且随着旋转速度的增加,这种趋势增强。对接头的抗拉强度研究表明,在1300 r.min-1以内时,随着旋转速度增加,接头抗拉强度随之增加,最大值为166 MPa,进一步增加到1500 r.min-1时,强度又有所降低,为154 MPa。

Influence of Rotational Speed on Welding Joint Surface Appearance, Microstructure and Mechanical Properties of ( WC + B4C) p/6063Al Composite

The rotational speed had a significant influence on welding joint surface appearance,microstructure and mechanical properties.(WC+B4C) p/6063Al MMCs were jointed by friction stir welding on the condition of rotation speed set as 900,1100,1300 and 1500 · min-1,while the welding speed was 100 mm · min-1.The welding joint surface appearance and several flaws were observed,and microstructure and mechanical properties were investigated.The results showed that with the increase of rotational speed,heat input increased,which led to the improvement of metal motion ability.Therefore,the surface got rough and more flaws,such as flash and groove.The results of the microstructure showed that due to the rotation effect of the pin,the distribution of reinforced particles got more homogenous and more particles got fragmented.What’s more,the trends grew with the increase of rotation speed.At the same time,the results of tensile strength showed that with the increase of rotation speed below 1300 r · min-1,the tensile strength got larger.The max tensile strength was 166 MPa.While rotation speed was increased at 1500 r · min-1,the tensile strength got a little lower,it was 166 MPa.