TC4线性摩擦焊接头微观特征

Microscopic feature of TC4 linear friction welded joints

关键词:  线性摩擦焊  微观特征  微孔  三叉形貌

Key words:  linear friction welding  microscopic feature  micro pore  three-branch structure

摘要:

对TC4线性摩擦焊接过程中的接头微观结构形态特征进行了分析,研究了接头微观特征参数随时间的变化趋势.结果表明,焊接过程为接头界面融合过程,界面呈现完全焊合区、过渡区及完全未焊合区3个区域.完全焊合区内界面完全融合、晶粒细小,为动态再结晶组织.过渡区内界面部分融合,有微孔出现.完全未焊合区内两侧金属未接触,夹杂着金属碎渣,晶粒无变形.振动方向飞边与垂直振动方向飞边分离是导致接头出现三叉形貌特征的原因.摩擦压力及顶锻力有使三叉形貌枝叉"闭合"的趋势,而摩擦剪切力有使三叉形貌枝叉"张开"的趋势.

Abstract:

Microscopic features of TC4 linear friction welded joints were analyzed and the variation of the characteristic parameters with welding time was studied.The results indicated that the joint interface includes the welded zone,the transition zone and the incomplete bonding zone.Fine dynamic recrystallization grains appeared in the welded zone where the joint interface fused completely.Micro pores formed in the transition zone where the joint interface fused partly.In the incomplete bonding zone,metals on both sides of the joint interface were not contacted and grains were out of distortion.Moreover,metal fragments developed in the joint interface.Three-branch structure forms in the joint interface due to the separation of the vibration direction flash and the vertical vibration direction flash.Friction pressure and upsetting pressure are inclined to close the branches,while friction shear force attributes for expanding the branches.