Effects of Nb content in Ti–Ni–Nb brazing alloys on the microstructure and mechanical properties of Ti–22Al–25Nb alloy brazed joints

The microstructure and mechanical properties of brazed joints of oxygen-free copper and oxygen-free copper, nickel-plated kovar, monel, nickel-plated stainless steel were respectively studied by using AgCu28 and AuCu20 filler metal. Effects of different filler metal on microstructure of the brazed joints were analyzed through metallurgical microscope, SEM, EPMA. The brazed joints tensile strengths were analyzed through tensile test. The results indicate that the brazing process of oxygen-free copper and nickel content alloy used AgCu28 filler metal, nickel element is easy to diffused into AgCu28, AgCu28 filler metal with nickel element wetting spreadability along grain boundary of the oxygen - free copper, resulting in the penetration of the grain boundary of the oxygen-free copper. The joints brazed by AuCu20 filler metal have the better performance than the joints brazed by AgCu28 filler metal.

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Reactive Air Brazing of TiAl Alloy Using Ag-CuO: Microstructure and Joint Properties

Crystals ◽

10.3390/cryst11121496 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1496

Author(s):

Haoran Yang ◽

Xiaoqing Si ◽

Chun Li ◽

Jian Cao

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Tial Alloy ◽

Oxide Layers ◽

Wetting Behavior ◽

Air Atmosphere ◽

Microstructure And Mechanical Properties ◽

Joint Properties ◽

Brazed Joints ◽

Maximum Shear Strength

TiAl alloy was successfully brazed with Ag-CuO filler in air atmosphere under simple technical conditions. The wettability of a series of Ag-CuO fillers on TiAl was analyzed. Ag-2mol%CuO filler possessed good wetting behavior on TiAl alloy. The microstructure and mechanical properties of the brazed joints were investigated. Oxide layers can be found on both sides, which can be divided into external TiO2-rich layer and internal Al2O3-rich layer. The maximum shear strength of the joint was obtained at 1020 °C holding for 20 min.

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Structure and Stresses of Large Size Brazed Joints of Cermets and Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.445.783 ◽

2012 ◽

Vol 445 ◽

pp. 783-788

Author(s):

Jerzy Nowacki

Keyword(s):

Mechanical Properties ◽

Filler Metal ◽

Constant Width ◽

Fem Analysis ◽

Local Stress ◽

Metal Structure ◽

Joint Geometry ◽

Microstructure And Mechanical Properties ◽

Brazed Joints

Stresses in brazing joints of different differed in properties were appraised as a result of technological experiments and FEM analysis. Evaluation of microstructure and mechanical properties of large dimensional vacuum brazed joints of Ferro Titanit Nicro 128 sinters and precipitation hardened stainless steel of X5CrNiMoCuNb14-5 using copper as the brazing filler metal. Structure of the joint was described. Shear strength Rt and tensile strength Rm of the joints have been defined. It have been state, that the basic factors decreasing quality of the joint, which can occur during vacuum brazing of the Ferro Titanit Nicro 128 sinter Cu brazing filler metal steel joints are diffusive processes leading to exchange of the cermets and brazing filler metal elements and creation of intermetallic in the joint. It can have an unfavourable influence on ductility and quality of the joint. The effect of joint geometry structure on stresses and deformations as well as on the process of plate cracking has been determined. Results of numerical calculations of three-dimensional models of brazed joints for different sizes of surfaces brazed at a constant width of solder gap are presented. Results of the investigate proved that joints microstructure and mechanical properties depend on filler and parent materials, diffusion process during brazing, leading to exchange of the cermets components and filler metal as well as joint geometry. The thickness of the joints has an essential influence on the values of the local stress and the significant influence on the joint rigidity. In a case of the considered joints the values of the local stress differences have been considerable in dependence of a fixed load manner.

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