Microstructure and Interfacial Reactions During Vacuum Brazing of Stainless Steel to Titanium Using Ag-28 pct Cu Alloy

Abstract

Microstructural evolution and interfacial reactions during vacuum brazing of grade-2 Ti and 304L-type stainless steel (SS) using eutectic alloy Ag-28 wt pct Cu were investigated. A thin Ni-depleted zone of a-Fe(Cr, Ni) solid solution formed on the SS-side of the braze zone (BZ). Cu from the braze alloy, in combination with the dissolved Fe and Ti from the base materials, formed a layer of ternary compound s 2 , adjacent to Ti in the BZ. In addition, four binary intermetallic compounds, Cu 3 Ti 2 , Cu 4 Ti 3 , CuTi and CuTi 2 formed as parallel contiguous layers in the BZ. The unreacted Ag solidified as islands within the layers of Cu 3 Ti 2 and Cu 4 Ti 3 . Formation of an amorphous phase at certain locations in the BZ could be revealed. The b-Ti(Cu) layer, formed due to diffusion of Cu into Ti-based material, transformed to an a-Ti + CuTi 2 eutectoid with lamellar morphology. Tensile test showed that the brazed joints had strength of 112 MPa and failed at the BZ. The possible sequence of events that led to the final microstructure and the mode of failure of these joints were delineated.

Effect of temperature on morphology and wear of a Cu-Ti-TiC MMC sintered by abnormal glow discharge

“…Furthermore, this temperature range was used in reason of the interest found to evaluate these points below the high transition temperatures of titanium (890°C). On the other hand, the studies [19,27] indicate these temperature ranges of interest due to the possible to promote high modulus intermetallic phases with strong interaction with copper matrix. Finally, another factor of interest in the selection was linked to the study of the morphological and mechanical influence of the use of low temperatures in the sintering of parts by AGD, using lower temperatures in comparison to previous studies in metallic systems [9,11,28], which had required higher energy contributions in the consolidation of metallic and ceramic particles.…”

Interfacial Reactions and Fracture Behavior of Ti Alloy-Ag28Cu Brazing Joints: Influence of Titanium Alloy Composition

“…The tomographic scans were carried out at energy of 35 keV. A pco.edge detector (2560 × 2160 pixels: 845 × 713 µ m²) was used to obtain a voxel size of (0.33 µ m) 3 . 8000 projections were acquired at 0.15 frames/s operating in half acquisition mode to double the field of view of the detector.…”

“…Brazing is currently being investigated as a joining technique for manufacturing aerospace components made of Ti alloys [1,2]. This technique is used for joining similar or, importantly, dissimilar [3,4] metallic parts by melting a brazing solder with a melting point lower than that of the base materials. Various solders are usually applied for Ti and Ti alloys, in particular Al-based (e.g., Al-1Mn), Pd-based (e.g., Pd-60Cu-10Co), Ti based (e.g., Ti-15Cu-15Ni) and near-eutectic Ag-Cu-based alloys [5,6].…”

“…The latter are particularly attractive owing to their low melting point, suitable wetting behavior and relatively high strength [5]. However, complex interfacial reactions take place as it has been reported in detail by several authors [3,[7][8][9][10]:…”

Infrared Dissimilar Joining of Ti50Ni50 and 316L Stainless Steel with Copper Barrier Layer in between Two Silver-Based Fillers

“…Dissimilar joining of Ti and many engineering alloys has been extensively studied in recent years [7][8][9]. Titanium (Ti) alloys directly bonded to SS will form TiFe/TiFe 2 intermetallics and result in inherent brittleness of the joint [10][11][12].…”