摘要
采用ZnAl22药芯焊丝对3 mm厚的AA5052铝合金和304不锈钢进行钨极氩弧(tungsten inert gas,TIG)熔-钎焊,研究不同焊接电流和送丝速度对对接接头宏观形貌、焊缝/钢界面微观组织以及接头抗拉性能和断裂行为的影响。结果表明:当焊接电流为110 A,送丝速度为24 mm/s时,对接接头平均抗拉强度达到最大值166 MPa,断裂位置主要为焊缝/钢界面,为典型的脆性断裂。焊缝/钢界面由η-Fe_(2)Al_(5)Zn_(0.4)、η-Zn(Al)和α-Al构成。随着焊接电流的增加,接头抗拉强度先升高后降低。η-Fe_(2)Al_(5)Zn_(0.4)界面层中出现白色颗粒状δ-FeZn_(10),Zn元素在η-Fe_(2)Al_(5)Zn_(0.4)/钢界面偏聚,利用透射电镜确定η-Fe_(2)Al_(5)Zn_(0.4)/钢界面处富Zn相为Γ-Fe_(3)Zn_(10),过大的焊接电流导致η-Fe_(2)Al_(5)Zn_(0.4)/钢界面产生开裂。随着送丝速度的增加,η-Fe_(2)Al_(5)Zn_(0.4)厚度逐渐减小,焊缝/钢界面物相组成不发生改变。基于热力学分析得出焊缝/钢界面金属间化合物(intermetallic compounds,IMCs)形成先后顺序为η-Fe_(2)Al_(5)Zn_(0.4)、δ-FeZn_(10)、Γ-Fe_(3)Zn_(10)。
AA5052 aluminum alloy and 304 stainless steel with the thickness of 3 mm are welded with ZnAl22 flux-cored wire by tungsten inert gas(TIG)fusion-brazed welding.The effect of different welding currents and wire feeding speeds on the macro morphology of butt joints,microstructure of weld seam/steel interface,tensile properties and fracture behavior of the joints is studied.The results show that when the welding current is 110 A and the wire feeding speed is 24 mm/s,the maximum average tensile strength of the butt joints reaches 166 MPa.Fracture primarily occurs at the weld seam/steel interface,exhibiting typical brittle fracture characteristics.The weld seam/steel interface is composed ofη-Fe_(2)Al_(5)Zn_(0.4),η-Zn(Al)andα-Al.With the increase of the welding current,the tensile strength of the joint first increases and then decreases.The white granularδ-FeZn_(10)appears in theη-Fe_(2)Al_(5)Zn_(0.4)interfacial layer,and Zn elements are segregated at theη-Fe_(2)Al_(5)Zn_(0.4)/steel interface.The Zn-rich phases at theη-Fe_(2)Al_(5)Zn_(0.4)/steel interface are determined to beΓ-Fe_(3)Zn_(10)by transmission electron microscopy.It is found that excessively high welding current leads to cracking at theη-Fe_(2)Al_(5)Zn_(0.4)/steel interface.With the increase of wire feeding speeds,the thickness ofη-Fe_(2)Al_(5)Zn_(0.4)decreases gradually,and the phase composition at the weld seam/steel interface remains unchanged.Based on thermodynamic analysis,it is concluded that the formation sequence of intermetallic compounds(IMCs)at the weld seam/steel interface isη-Fe_(2)Al_(5)Zn_(0.4),δ-FeZn_(10),Γ-Fe_(3)Zn_(10).
作者
马月婷
董红刚
李鹏
MA Yueting;DONG Honggang;LI Peng(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China)
出处
《材料工程》
北大核心
2026年第3期144-160,共17页
Journal of Materials Engineering
基金
国家自然科学基金面上项目(52275314)。
关键词
铝合金/钢异种金属
钨极氩弧熔-钎焊
金属间化合物
抗拉强度
aluminum alloy/steel dissimilar metal
TIG fusion-brazed welding
intermetallic compounds
tensile strength
