异种合金与纯钛激光焊接熔焊区元素混熔分布及组织结构特征

Element mixing distribution and structure feature of fusion zone in laser welding between different alloys and pure titanium

目的 观察异种金属激光焊接后的组织微观结构、元素的混熔分布和激光对金铂、镍铬、纯钛、钴铬等异种合金 (金属 )焊接的可行性。方法 采用扫描电镜对熔焊区的金相组织结构变化观察。同时用超薄窗X射线能谱仪扫描分析、测试混熔后的元素分布和趋向。结果 ①金铂、镍铬、钴铬异种合金相互焊接后熔焊区的组织过度良好、界限不清。有网状、柱状、枝状结构生成 ,属冶金结合。而所有与钛金属焊接后的混熔区组织过度不良、晶粒增大明显、形态不规则 ,有微裂发生。②在熔焊区内 ,钛元素多成旋涡状出现。而其他合金的元素混熔分布均匀。元素峰波波值受所在部位所决定。结论 钛金属与其他合金进行合金化时 ,极易发生脆性相。异种金属除不易与钛金属配对焊接以外 ,激光对其他齿科异种合金相互焊接的效果是理想的。

Objective To study micro morphology and element mixing distribution of different alloys welded in laser and analyze the feasibility of laser welding different alloys. Methods Alloys and titanium were matched into 4 groups: Au Pt with Ni Cr; Au Pt with pure Ti; pure Ti with Ni Cr; Ni Cr with Co Cr. They were welded in laser. Changes in metallography after hybridization of crystalline grain, ranges of heat affected zone and pores were observed through SEM with ultra thin windowed X ray energy atlas. Meanwhile 10 testing points were chosen with area of 300 μm × 900 μm along the welding surface from the side A alloy to the side B alloy, than the element mixing distribution and tendency were analyzed with X ray energy atlas. Results 1. Hybridization of different alloys: (l) in the group of Au Pt with Ti, there was titanium element mixing into Au Pt tissue gradually and evenly on the Au Pt side of the interface without clear boundary and increasing in size of crystalline grain. However, there was titanium crystalline grain increasing in size, irregular morphology and small sacks on the titanium side with clear boundary. (2) in the group of Ni Cr with Ti, there was mixing regularly, slow transition and interlocks between crystalline grains on the Ni Cr side of the in terface. Poor transition, clear boundary and small cracks were observed on titanium side. (3) in the group of Co Cr with Ni Cr, there was good transition, obscure boundary on both sides resulting from network, cylinder and branch structure growing. 2. Element mixing distribution of different alloys. In fusion zone, the metal elements in matched groups mixed well and hybridized into new alloys except titanium blocks. The location of wave peak depended on the composition of alloys. Most of elements were from the alloy far from the fusion zone. Conclusion The hybridization between pure titanium and any other alloys is not good The effect of laser welding different alloys is ideal except with pure titanium.