Effect of Cooling Rate on the Microstructure and Mechanical Properties of Sn-0.7wt.%Cu Solder Alloy

2016 ◽  
Vol 675-676 ◽  
pp. 513-516 ◽  
Author(s):  
Phairote Sungkhaphaitoon ◽  
Thawatchai Plookphol

The dependence of microstructure and mechanical properties of Sn-0.7wt.%Cu solder alloys on different cooling rates were investigated. Two cooling rates were employed during solidification: 0.04 °C/s (mold-cooled system) and 1.66 °C/s (water-cooled system). The results showed that the ultimate tensile strength of Sn-0.7wt.%Cu solder alloy increased but the elongation decreased when water-cooled system was used. The microstructure of Sn-0.7wt.%Cu solder alloys solidified by both cooling systems exhibited two phases of Sn-rich and Cu6Sn5 intermetallic compounds (IMCs). However, finer grains were observed in the water-cooled specimens.

2018 ◽  
Vol 934 ◽  
pp. 73-78
Author(s):  
Phairote Sungkhaphaitoon

To study the effect of cooling speed on the microstructure and mechanical properties of Sn-0.7Cu-0.05Ni solder alloy, molten alloys were cooled at two different rates, using water-cooling and mold-cooling. The mechanical properties of the obtained alloys were analyzed with a universal testing machine (UTM) and by Vickers microhardness testing (HV). The microstructures were characterized using an optical microscope (OM) and energy dispersive X-ray spectroscopy (EDX).The melting point was ascertained by differential scanning calorimetry (DSC). The cooling rate of the water-cooled system (0.28 o C/s) was faster than the cooling rate of the mold-cooled system (0.05 °C/s). The grain size of the alloy produced by the faster cooling rate was finer than that of the alloy obtained from the slower cooling rate. This finer grain size gave the alloy superior ultimate tensile strength (UTS) and hardness but inferior ductility (%EL). The microstructure of both Sn-0.7Cu-0.05Ni solder alloys exhibited three phases of β-Sn, Cu6Sn5 and (Cu,Ni)6Sn5 intermetallic compounds. The melting point and undercooling of the solder alloys was 233.8 °C and 35.7 °C, respectively.


Author(s):  
Zheng Liu ◽  
Yang Li ◽  
Yifeng Xiong ◽  
Huiming Gao

Abstract The effect of trace Nb nanoparticles on thermal properties, wettability, microstructure and mechanical properties of Sn-0.7Cu solder alloy was investigated. The results show that the melting temperature of Sn-0.7Cu composite solder alloy is between 229 ? and 231 ?, and the effect of Nb nanoparticles on the melting temperature is not obvious. The wettability of the solder alloy was remarkably improved by adding Nb nanoparticles. The coarse ß-Sn phase and ß-Sn/Cu6Sn5 eutectic in the Sn-0.7Cu composite solder alloys is refined by adding appropriate Nb nanoparticles, and then the ultimate tensile strength (37.3 MPa) and the elongation (2.47 mm) of Sn-0.7Cu alloy are increased to the maximum 45.4 MPa and 4.59 mm of Sn-0.7Cu-0.12Nb alloy. The fracture mechanism of Sn-0.7Cu-xNb composite solder alloys are plastic fracture.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 790 ◽  
Author(s):  
Changping Tang ◽  
Kai Wu ◽  
Wenhui Liu ◽  
Di Feng ◽  
Xuezhao Wang ◽  
...  

The effects of Gd, Y content on the microstructure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy were investigated using hardness measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and uniaxial tensile testing. The results indicate that the alloys in as-cast condition mainly consist of α-Mg matrix and non-equilibrium eutectic Mg5.05RE (RE = Gd, Y, Nd). After solution treatment, the non-equilibrium eutectics dissolved into the matrix but some block shaped RE-rich particles were left at the grain boundaries and within grains. These particles are especially Y-rich and deteriorate the mechanical properties of the alloys. Both the compositions of the eutectic and the block shaped particle were independent of the total Gd, Y content of the alloys, but the number of the particles increases as the total Gd, Y content increases. The ultimate tensile strength increases as the total Gd, Y content decreases. A Mg-5.56Gd-3.38Y-1.11Nd-0.48Zr alloy with the highest ultimate tensile strength of 280 MPa and an elongation of 1.3% was fabricated. The high strength is attributed to the age hardening behavior and the decrease in block shaped particles.


Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 385
Author(s):  
Yushi Qi ◽  
Heng Wang ◽  
Lili Chen ◽  
Hongming Zhang ◽  
Gang Chen ◽  
...  

A ZK61-Y magnesium (Mg) alloy wheel hub was prepared via liquid forging—isothermal forging process. The effects of Y-element contents on the microstructure and mechanical properties of liquid forging blanks were investigated. The formation order of the second phase was I-phase (Mg3Zn6Y) → W-phase (Mg3Zn3Y2) → Z-phase (Mg12ZnY) with the increase of the Y-element content. Meanwhile, the I-phase and Z-phase formed in the liquid forging process were beneficial to the grain refinement. The numerical simulation of the isothermal forging process was carried out to analyze the effects of forming temperature on the temperature and stress field in the forming parts using the software Deform-3D. Isothermal forging experiments and post heat treatments were conducted. The influence of isothermal forging temperature, heat treatment temperature and preservation time on the microstructure and mechanical properties of the forming parts were also studied. The dynamic recrystallization (DRX), second-phase hardening, and work hardening account for the improvement of properties after the isothermal forging process. The forming part forged at 380 °C displayed the outstanding properties. The elongation, yield strength, and ultimate tensile strength were 18.5%, 150 MPa and 315 MPa, respectively. The samples displayed an increased elongation and decreased strength after heat treatments. The 520 °C—1 h sample possessed the best mechanical properties, the elongation was 25.5%, the yield stress was 125 MPa and the ultimate tensile strength was 282 MPa. This can be ascribed to the recrystallization and the elimination of working hardening. Meanwhile, the second phase transformation (I-phase → W-phase → Mg2Y + MgZn2), dissolution, and decomposition can be observed, as well.


Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 742 ◽  
Author(s):  
Khan ◽  
Yu ◽  
Wang ◽  
Jiang

The effect of cooling rate, ranging from 6 to 1 °C/s, on microstructure and mechanical properties in the coarse-grained heat affected zone (CGHAZ) of electroslag welded pearlitic rail steel has been investigated by using confocal scanning laser microcopy (CSLM) and Gleeble 3500 thermo-mechanical simulator. During heating, the formed austenite was inhomogeneous with fractions of untransformed ferrite, which has influenced the pearlite transformation during cooling by providing additional nucleation sites to pearlite. During cooling, at 6 °C/s, the microstructure was composed of martensite and bainite with little pearlite. From 4 to 1 °C/s, microstructures were completely pearlite. Lowering the cooling rate of the CGHAZ from 4 to 1 °C/s increased the pearlite start temperature and reduced the pearlite growth rate. Meanwhile, this increase in pearlite start temperature enlarged the pearlite interlamellar spacing. Alternatively, increasing pearlite interlamellar spacing in the CGHAZ by lowering the cooling rate from 6 to 1 °C/s reduced the hardness and tensile strength, whereas toughness was found unaffected by the pearlite interlamellar spacing. It has been found that a cooling rate of 4 °C/s leads to the formation of pearlite with fine interlamellar spacing of 117 nm in the CGHAZ of electroslag welded pearlitic rail steel where hardness is 425 HV, tensile strength is 1077 MPa, and toughness is 9.1 J.


2017 ◽  
Vol 898 ◽  
pp. 124-130 ◽  
Author(s):  
Shu Min Xu ◽  
Xin Ying Teng ◽  
Xing Jing Ge ◽  
Jin Yang Zhang

In this paper, the microstructure and mechanical properties of the as-cast and heat treatment of Mg-Zn-Nd alloy was investigated. The alloy was manufactured by a conventional casting method, and then subjected to a heat treatment. The results showed that the microstructure of as-cast alloy was comprised of α-Mg matrix and Mg12Nd phase. With increase of Nd content, the grain size gradually decreased from 25.38 μm to 9.82 μm. The ultimate tensile strength and elongation at room temperature of the Mg94Zn2Nd4 alloy can be reached to 219.63 MPa and 5.31%. After heat treatment, part of the second phase dissolved into the magnesium matrix and the grain size became a little larger than that of the as-cast. The ultimate tensile strength was declined by about 2.5%, and the elongation was increased to 5.47%.


2017 ◽  
Vol 751 ◽  
pp. 9-13
Author(s):  
Kogaew Inkong ◽  
Phairote Sungkhaphaitoon

The effect of cooling rate on the microstructural and mechanical properties of Sn-0.3Ag-0.7Cu-0.05Ni lead-free solder alloy was studied. The microstructure of specimens was characterized by using an optical microscope (OM) and an energy dispersive X-ray spectroscopy (EDX). The mechanical properties were performed by using a universal testing machine (UTM). The results showed that the cooling rate of water-cooled specimens was about 2.37 °C/s and the cooling rate of mold-cooled specimens was about 0.05 °C/s. To compare the different cooling rates, it was found that the grain size of water-cooled specimens was finer than that of the mold-cooled specimens, this resulted in an increment of mechanical properties of solder alloy. A higher tensile strength (33.10 MPa) and a higher elongation (34%) were observed when water-cooled and mold-cooled systems were used, respectively. The microstructure of Sn-0.3Ag-0.7Cu-0.05Ni lead-free solder alloy solidified by both cooling systems exhibited three phases: β-Sn, Ag3Sn and (Cu,Ni)6Sn5 IMCs.


2018 ◽  
Vol 37 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Hansong Xue ◽  
Xinyu Li ◽  
Weina Zhang ◽  
Zhihui Xing ◽  
Jinsong Rao ◽  
...  

AbstractThe effects of Bi on the microstructure and mechanical properties of AZ80-2Sn alloy were investigated. The results show that the addition of Bi within the as-cast AZ80-2Sn alloy promotes the formation of Mg3Bi2 phase, which can refine the grains and make the eutectic phases discontinuous. The addition of 0.5 % Bi within the as-extruded AZ80-2Sn alloy, the average grain size decreases to 12 μm and the fine granular Mg17Al12 and Mg3Bi2 phases are dispersed in the α-Mg matrix. With an increase in Bi content, the Mg17Al12 and Mg3Bi2 phases become coarsened and the grain size increases. The as-extruded AZ80-2Sn-0.5 %Bi alloy has the optimal properties, and the ultimate tensile strength, yield strength and elongation are 379.6 MPa, 247.1 MPa and 14.8 %, respectively.


2013 ◽  
Vol 747-748 ◽  
pp. 245-250 ◽  
Author(s):  
Jun Luo ◽  
Rong Shi Chen ◽  
En Hou Han

The microstructure and mechanical properties of as-cast Mg-3Sn-xGd (x=0, 0.2, 1 wt.%) alloys were studied by using OM, SEM, EDX, XRD etc. With the increase of Gd, the formation of Mg2Sn phase was impeded and the MgSnGd phase formed and the volume fraction of this new phase obviously increased. The ultimate tensile strength and elongation to failure increased with dilute Gd addition but sharply decreased when the Gd addition comes to 1.34 wt.%. The possible reasons for the variation in microstructure and mechanical properties were discussed.


2010 ◽  
Vol 152-153 ◽  
pp. 1083-1087
Author(s):  
Bo Wang ◽  
Yu Tao Zhao ◽  
Song Li Zhang ◽  
Gang Chen ◽  
Xiao Nong Cheng

In-situ (Al2O3+Al3Zr)p/A356 composites were synthesized by melt reaction technology and the effects of yttrium on microstructure and mechanical properties of the composites are investigated. The results indicate that the reinforced particulates Al2O3 and Al3Zr become smaller in size with yttrium addition, the sizes are about 0.5~2μm. The distribution becomes more homogeneous, the morphologies are spheroid-shape and ellipsoid-shape, the ambitus is blunt. The mechanical properties test results show the mechanical properties of the composites are greatly enhanced. With 0.4wt.% yttrium addition, the ultimate tensile strength and yield strength of the composites reach to 388MPa and 296MPa, which are increased 35.6% and 37.0% comparing with no yttrium addition, respectively. The effect mechanisms of yttrium are discussed.


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