Microstructure and Mechanical Properties of Brazed Joints Used in Electronic Devices

2014 ◽  
Vol 936 ◽  
pp. 1671-1675
Author(s):  
Xue Rui Wu ◽  
Wen Qing Qu ◽  
Hai Tao Li

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.

2012 ◽  
Vol 57 (4) ◽  
pp. 1087-1093 ◽  
Author(s):  
W. Gąsior ◽  
A. Winiowski

The analysis of the influence of lithium on wetting properties of Ag-Cu brazing alloys and the shear strength of stainless steel/braze/stainless steel joint was conducted. The brazing alloys of designations and composition according to ANSI/AWS A5.8: BAg-8a (71÷3 wt.% Ag, 0.25÷0.50 wt.% Li, Cu) and BAg-19 (92÷93 wt.% Ag, 0.15÷0.30 wt.% Li, Cu) and a braze alloy containing 70÷72 wt.% Ag, 0.6÷0.7 wt.% Li and Cu were subjected to the investigations. The wettability properties of the brazing silver alloys were examined in a spread test. The shear strength of joints were measured on the joints of stainless steel in the tensile test. The comparison of results showed a beneficial effect of lithium on the spreading properties and the wettability of braze alloys as well as the quality and shear strength of the brazed joints. The observed slag inclusions in the solid braze did not affect considerably the mechanical properties of the prepared joints because of the intensive deoxidation of the brazing surfaces of stainless steel elements.


2019 ◽  
Vol 29 ◽  
pp. 1-12
Author(s):  
Juan Manuel Salgado López ◽  
Marc Preud homme ◽  
Francisco Lopez Monroy ◽  
Jose Luis Ojeda Elizarráraz ◽  
Arturo Toscano Giles

In literature, it has been reported that a current intensity lower than 120 A leads to a microstructure without grain growth in the heat affected zone (HAZ) of ferritic stainless steel welds. Nevertheless, in technical literature there is little information about the reduction in mechanical properties of ferritic stainless steel welds without filler metal due to grain growth in the HAZ. In this work, thin plates of ferritic stainless 439 steel were welded using pulse current gas tungsten arc welding (P-GTAW) without filler metal. The microstructures in the HAZ were analyzed and the mechanical properties on the welded joint were found by tensile test. This was carried out by cutting samples for the tensile test from the weldments and then tested in a universal testing machine. The fracture surface were observed using scanning electron microscope.


2012 ◽  
Vol 445 ◽  
pp. 783-788
Author(s):  
Jerzy Nowacki

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.


2015 ◽  
Vol 60 (4) ◽  
pp. 2593-2598 ◽  
Author(s):  
M. Różański ◽  
D. Majewski ◽  
K. Krasnowski

This study presents the basic physico-chemical properties and describes the brazeability of titanium. The work contains the results of macro and microscopic metallographic examination as well as the results of strength-related tests of vacuum and induction brazed joints made of Grade 2 technical titanium using the Cu 0.99 and Ag 272 filler metal interlayers and F60T flux intended for titanium brazing in the air atmosphere.


2011 ◽  
Vol 418-420 ◽  
pp. 1242-1245
Author(s):  
Zhuo Jun Chen ◽  
Chang Jin Yang ◽  
Xiao Long Gu ◽  
Cheng Dong Wu ◽  
Long Long Feng

Vacuum brazing of 316L stainless steel with BNi-2 brazing filler metal.The effects of brazing temperature and brazing clearance on microstructure and mechanical properties of vacuum brazed joints of 316L stainless steel were studied. The results show that: As brazing temperature being 1 070 °C, with the increasing of the brazing clearance, the joint shear strength value become lower and lower. Brazing clearance compounds mainly contain intermetallic and solid solutions.


2016 ◽  
Vol 850 ◽  
pp. 700-705 ◽  
Author(s):  
Qian Qian Sun ◽  
Sheng Lu

The effects of brazing time on elements diffusion and bonding strength of vacuum brazed joints of 15-5PH stainless steel using filler metal BNi-2 were investigated. The results showed that the brazing time determined the content of diffused elements. If holding time is short the distribution of melting point depressants (MPD) concentrated on the middle zone of the joint, and the generation of brittle phases in the joint was unavoidable. With increasing time, MPD can diffuse to base metal adequately and full solid solution of nickel formed in the brazing joint. Joint strength firstly increased and then decreased with prolonging holding time.


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