scholarly journals Microstructure and mechanical properties of brazing joint of silver-based composite filler metal

2020 ◽  
Vol 9 (1) ◽  
pp. 1034-1043
Author(s):  
Hua Yu ◽  
Liangliang Zhang ◽  
Fangfang Cai ◽  
Sujuan Zhong ◽  
Jia Ma ◽  
...  

AbstractIn this article, environmental friendly BAg25Cu40Zn34Sn (BAg-25) and BAg30Cu37Zn32Sn (BAg-30) flux-core solder metal capable of facilitating automatic production of brazing manufacturing processes were prepared. The butt and lap induction brazing tests were carried out on the substrate with BAg-25 and BAg-30. Wettability, microstructure and mechanical properties of the solders on the base metal were studied by field emission scanning electron microscope (SEM-EDS), electron backscattering diffraction (EBSD), tensile testing machine and microhardness tester. Results indicated that the wetting property of BAg-30 with 30% silver content was better than that of BAg-25 with 25% silver content. At the same time, besides copper and silver-based solid solutions, the brazed joint of BAg-30 solder also contain Cu + Ag eutectic phase. In the brazed joint of BAg-25 solder, the grain size is smaller, which makes the tensile strength and the shear strength of the joints better. Therefore, the BAg-25 flux-core solder metal will further reduce the industrial cost and meet the requirements of mechanical properties.

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 568
Author(s):  
Xinwei She ◽  
Xianquan Jiang ◽  
Bao Qi ◽  
Kang Chen

The effect of Er on microstructure and mechanical properties of the 5052 aluminum alloy with a big width-to-thickness ratio was investigated by a metallurgical microscope, scanning electron microscope and tensile testing machine. The results showed that the precipitates were slightly refined after Er addition and Al3Fe was transformed into Al6Fe and AlEr with/without a small amount of Fe or Si. The effect of Er on grain refinement was related to its content. When Er content was lower or higher than 0.4%, the grain would coarsen. Homogenization could refine the grain by controlling Er content and distribution in the Al matrix. Long time homogenization at high temperature would significantly reduce the strength of the 5052 aluminum alloy and 5052 aluminum alloys with low Er content, but help to improve the plasticity of those with high Er content. The ultimate tensile strength, yield strength and elongation of the as-cast 5052 aluminum alloy were 197 MPa, 117 MPa and 22.5% respectively. The strength was the highest, when Er content was 0.4 wt. % and the elongation was the best at 0.1 wt. % Er content.


2017 ◽  
Vol 904 ◽  
pp. 15-18
Author(s):  
Bo Bo Meng ◽  
Quan An Li ◽  
Xiao Ya Chen

The effects of heat treatment on microstructure and mechanical properties of Mg-9Gd-4Y-0.5Zr alloy were studied by XRD, OM, SEM and tensile testing machine. The results show that the alloy mainly consists of α-Mg matrix, Mg5Gd and Mg24Y5. Through solid solution and aging heat treatment process, the tensile strength, yield strength and elongation rate respectively achieves 263.1MPa, 235.2MPa and 3.11%.


2014 ◽  
Vol 789 ◽  
pp. 384-390 ◽  
Author(s):  
Yun Zhu Ma ◽  
Qing Shan Cai ◽  
Wen Sheng Liu ◽  
Shu Hua Liu

Due to its excellent thermophysical properties, tungsten has been used as structural materials for divertor components of fusion reactors. With the development of technology, the helium cooled high performance divertor requires the high reliable joining between tungsten and ferritic martensitic high chromium steel. However, the difference of thermal expansion coefficients between tungsten and steel causes high thermally residual stresses, which will yield failure of the joint. Therefore, the preparation of the joint between tungsten and steel is a key issue for divertor application. A brazing process, using rapidly solidified Ni-based foil-type filler and a vanadium slice as intermediate materials, was developed to investigate the joining of tungsten and steel for divertor components, and the microstructure and mechanical properties of the joint were also studied. The elements and phases compositions in the boning regions were analyzed by electron probe microanalysis and X-ray diffraction. Micro-hardness distribution and tensile strength of joint were measured by nanoindenter and mechanical testing machine, respectively. The results indicated that the integral bonding was achieved at the bonding regions of the brazed joint. The typical microstructure of the joint was consisted of W/V and V/steel brazed seams separated by a V slice. The hard and brittle vanadium borides with 25 GPa hardness were produced at the W/V and V/steel brazed seams. The as-bonded W/steel joint with tensile strength of 143MPa was obtained, and specimens appeared a brittle fracture mode and fractured in the brittle vanadium boride layers during tensile testing.


Author(s):  
Tao Chen ◽  
Chen Xue-dong ◽  
Xiao-ming Lian ◽  
Zhi-chao Fan

The influence of Ti element with the content from 0.018 wt.% to 0.112 wt.% on microstructure and mechanical properties of centrifugally cast 25Cr-35Ni-Nb alloy was investigated in this paper. The experiments were carried out by optical emission spectrometer, metallographic image analyzer, field emission gun scanning electron microscopy (FEG-SEM) equipped with an Oxford INCA energy dispersive X-ray spectrometer (EDS), tensile testing machine and creep testing machine. The results show that the microstructure and high temperature creep rupture properties of as-cast 25Cr-35Ni-Nb alloy are significantly affected by the addition of Ti. No precipitation of Ti carbides was observed in the alloy with the Ti content of 0.018 wt.%, whereas the skeleton (Nb, Ti) C were precipitated at grain boundaries when increasing the Ti content. Under the creep rupture condition of 1100 °C and 17 MPa, the rupture lives of 25Cr-35Ni-Nb alloy with Ti contents ranging from 0.04 wt.% to 0.112 wt.% were relatively higher. In addition, the role of Ti in ethylene pyrolysis furnace tube was also discussed in this paper.


2010 ◽  
Vol 652 ◽  
pp. 174-179
Author(s):  
Mohsen Sadrossadat ◽  
Sten Johansson

The soundness and the performance of castings are significantly affected by generation and accumulation of residual stresses. This has been proven that mechanical properties and residual stresses level of the casting components are affected by thermal gradient across the casting component during cooling and some intrinsic physical properties of the material. In the present work, microstructural development, mechanical properties, residual stress evolution and cooling curves associated with different legs of a mixed–section grid castings have been investigated employing scanning electron microscope, optical microscope, 3D measurement equipment, computerized thermal data acquisition instrument and tensile testing machine. Experimental results show that the accumulated residual stress in circular, triangular and rectangular grid shapes is increasing respectively. From the results it can be seen that there are clear influences of grid’s geometry on the microstructure and mechanical properties. The geometrical stiffness can affect a lot the residual stress level and the casting modulus has a big influence on the microstructure and mechanical properties.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tiebao Wang ◽  
Chunxiang Cui ◽  
Kuo Jia ◽  
Lichen Zhao

The nanostructured Fe-V-Nb master alloy was prepared in vacuum rapid quenching furnace and then was added in the steel melts as modificators before casting. Next, the effects of the nanostructured Fe-V-Nb modificators on the microstructure and mechanical properties of the steel were studied. The results show that the grain size of the steel has been effectively refined, which is mainly because the dispersed nanoscale particles can produce more nucleation sites during the solidification of the liquid steel. Tensile properties and fracture morphology reveal that the yield strength and toughness of the steel modified by nanostructured Fe-V-Nb modificators are better than that of the microalloyed steel. TEM analysis shows that vanadium and niobium in the modificators exist in the form of (V, Nb) C which effectively increases the nucleation rate and leads to better mechanical properties of the steel.


2013 ◽  
Vol 589-590 ◽  
pp. 572-577 ◽  
Author(s):  
Hua He Liu ◽  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Ya Cong Chai

Al2O3-MgO, Al2O3-Y2O3 and Al2O3-MgO-Y2O3 composite ceramics were fabricated respectively by hot-press sintering technique. With the analysis of the mechanical properties and microstructure, it was found that single additive MgO could be more favorable to the grains’ refinement and densification than Y2O3; the composite additive including both MgO and Y2O3 was better than single additive MgO or Y2O3, because their interactions could improve the mechanical properties of the Al2O3 ceramics; The sintering temperature could be reduced by adding the suitable amount of composite additives.


2005 ◽  
Vol 475-479 ◽  
pp. 1001-1004
Author(s):  
Ninglin Zhou ◽  
Xiao Xian Xia ◽  
Li Li ◽  
Shao Hua Wei ◽  
Jian Shen

A novel exfoliated polyurethane (PU)/clay Interpenetrating Polymer Networks (IPNs) nanocomposite has been synthesized with polyurethane and organoclay. MTPAC is used as swelling agent to treat Na-montmorillonite for forming organoclay. The results indicate that there is very good compatibility between organoclay and PU. Nanoscale silicate dispersion was analyzed by XRD. The mechanical properties of the nanocomposites have been measured by tensile testing machine. The nanocomposites show obviously improved physical and mechanical properties when compared with the pure polymer. Additionally, PU /MTPAC- clay shows lower water absorption properties than pure PU do. In addition, the reinforcing and intercalating mechanism of silicate layers in polyurethane matrix are discussed.


2021 ◽  
Vol 10 (1) ◽  
pp. 1318-1328
Author(s):  
Hua Yu ◽  
Liangliang Zhang ◽  
Shuai Li ◽  
Fangfang Cai ◽  
Yunpeng Li ◽  
...  

Abstract To meet the requirements of automatic production, a new type of green BAl88Si cored solder was developed. The lap brazing experiments were carried out with copper and aluminum as brazing substrates. The microstructure, phase composition, and corrosion behavior of solder joint interface were studied by field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, electron backscattering diffraction, tensile testing machine, and electrochemical workstation. The results show that the brazing joint of Cu/BAl88Si/Al is metallurgical bonding, and the brazing joint of Cu/BAl88Si/Al is composed of Cu9Al4, CuAl2, a-Al, (CuAl2 + a-Al + Si) ternary eutectic. In addition, there is no obvious preference for each grain in the brazing joint, and there are S texture {123}<634>, Copper texture {112}<111>, and Brass texture {110}<112>. The interface of Cu9Al4/CuAl2 is a non-coherent crystal plane and does not have good lattice matching. The average particle size of CuAl2 is 11.95 µm and that of Al is 28.3 µm. However, the kernel average misorientation (KAM) value at the brazed joint interface is obviously higher than that at the brazed joint interface copper, so the defect density at the brazed joint interface aluminum is higher than that at the brazed joint interface copper. At the same time, due to poor corrosion resistance at the interface on the aluminum side of the brazed joint, serious corrosion spots and corrosion cracks occur at the same time, which leads to the shear performance of the brazed joint decreasing by about 75% after salt spray test for 240 h.


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