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Indexed by:期刊论文

Date of Publication:2019-02-01

Journal:METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE

Included Journals:SCIE、Scopus

Volume:50A

Issue:2

Page Number:688-703

ISSN No.:1073-5623

Key Words:Binary alloys; Chromium compounds; Copper; Fillers; Gas metal arc welding; Gas welding; Mechanical properties; Silicon alloys; Tensile strength; Ternary alloys; Thermodynamic properties; Titanium alloys; Welds, 304 stainless steel; Brittle cleavage; Fractured surfaces; Gas tungsten arc welding; Microstructure and mechanical properties; Stainless steel joints; TC4 titanium alloy; Transition zones, Copper alloys

Abstract:TC4 titanium alloy was successfully welded to 304 stainless steel using gas tungsten arc welding with a CuSi3 filler wire. The Ti/weld transition zone in the joint consisted of -Ti, Ti2Cu, AlCu2Ti, TiCu, and Ti5Si3 intermetallic compounds (IMCs) when welded with low current. As the welding current increased, more Fe dissolved into the weld pool, and massive ternary Ti-Cu-Fe and AlCu2Ti IMCs formed in the Ti/weld transition zone. The segregated Ti5Si3 phase disappeared, and complex Fe-Ti-Si-Cr IMCs formed outside the Ti/weld transition zone. The microhardness was much higher in the Ti/weld transition zone than that in the TC4 substrate and copper weld, reaching a maximum value of 619 HV. The highest tensile strength was 328 MPa when the welding current was 120 A and the traveling speed was 4 mm/s. All joints failed through the Ti/weld transition zone, and brittle cleavage features were present on the fractured surfaces. Due to the large difference in thermophysical properties between the two base metals, cracks were easily generated, which restricted the improvement in the tensile strength of the TC4/304 SS joint.