scholarly journals Effect of Cr Addition on Microstructure and Properties of AuGa Solder

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1449
Author(s):  
Yu Tao ◽  
Songbai Xue ◽  
Han Liu ◽  
Weimin Long ◽  
Bo Wang
Keyword(s):  
Shear Strength ◽  
Space Exploration ◽  
Solder Matrix ◽  
Electronic Devices ◽  
Energy Resource ◽  
Casting Process ◽  
Interface Morphology ◽  
Cr Addition ◽  
Inhomogeneous Microstructure ◽  
Peak Value

In order to meet the service requirements of electronic devices working at 300 °C in the fields of energy resource prospecting and space exploration, Cr element was added to modify AuGa solder to improve its high-temperature performance. The results showed that the addition of 0.3 wt.% Cr element reduced the loss of Ga element in the smelting and casting process, and effectively improved the problem of the inhomogeneous microstructure of the solder matrix. On the basis of maintaining the good wettability of the solder, the addition of trace chromium effectively restrains the excessive flux of the solder, and the presence of chromium improves the oxidation resistance of the solder. Furthermore, Cr element optimized the interface morphology and improved the mechanical properties of the solder joint. The shear strength of the AuGa-0.3Cr/Ni joint was 87.2 MPa, which was 13.1% higher than that of the joint without Cr element. After 240 h of aging, the shear strength of the AuGa-0.3Cr joint was still the peak value at 84.1 MPa, which was 16.3% higher than that of the AuGa joint.

scholarly journals Comprehensive Properties of a Novel Quaternary Sn-Bi-Sb-Ag Solder: Wettability, Interfacial Structure and Mechanical Properties

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 791 ◽  
Author(s):  
Kaipeng Wang ◽  
Fengjiang Wang ◽  
Ying Huang ◽  
Kai Qi
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Low Temperature ◽  
Strain Rate ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Solder Matrix ◽  
Interfacial Structure ◽  
Solder Alloys ◽  
Cu Substrate

Sn-58Bi eutectic solder is the most recommended low temperature Pb-free solder but is also limited from the interfacial embrittlement of Bi segregation. Since the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides a similar melting point as Sn-58Bi eutectic, this paper systematically investigated the properties of this solder from wettability, bulk tensile properties, interfacial microstructure in solder joints with a Cu substrate, interfacial evolution in joints during isothermal aging and the shear strength on ball solder joints with effect of aging conditions. The results were also compared with Sn-58Bi solder. The wettability of solder alloys was evaluated with wetting balance testing, and the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a better wettability than Sn-58Bi solder on the wetting time. Tensile tests on bulk solder alloys indicated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a higher tensile strength and similar elongation compared with Sn-58Bi solder due to the finely distributed SnSb and Ag3Sn intermetallics in the solder matrix. The tensile strength of solder decreased with a decrease in the strain rate and with an increase in temperature, while the elongation of solder was independent of the temperature and strain rate. When soldering with a Cu substrate, a thin Cu6Sn5 intermetallic compound (IMC) is produced at the interface in the solder joint. Measurement on IMC thickness showed that the quaternary Sn-38Bi-1.5Sb-0.7Ag had a lower IMC growth rate during the following isothermal aging. Ball shear test on solder joints illustrated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints had higher shear strength than Sn-58Bi solder joints. Compared with the serious deterioration on shear strength of Sn-58Bi joints from isothermal aging, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints presented a superior high temperature stability. Therefore, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides better performances and the possibility to replace Sn-58Bi solder to realize low temperature soldering.

scholarly journals An investigation on cryptographic algorithms usage in IoT contexts

2018 ◽  
Vol 7 (1.7) ◽  
pp. 10
Author(s):  
R H Aswathy ◽  
N Malarvizhi
Keyword(s):  
Information Exchange ◽  
Short Range ◽  
Electronic Devices ◽  
Energy Resource ◽  
Block Size ◽  
Self Organization ◽  
Key Generation ◽  
Secure Information ◽  
Security Algorithm ◽  
Constrained Devices

The broad vision of IoT focuses the highly increasing the electronic devices and application in which leads to the growth of technology. The enormous amounts of constrained devices are interlinked, communicate and coordinate with each other to fulfill its tackier mainly concentrate on low energy, Resource constraint, self-organization and short range of communication. In this heterogeneous environment of Antiprivacy and security are the greatest challenge. The secure information exchange is most critical pitfall to ensure the system security. In this paper we discussed and analyzed about various security algorithms like Triple DES, AES, Blowfish and ECCwith their structure, block size, key generation, number of rounds with different settings. In order to analyze the efficiency of all said algorithms, we made an experiment on algorithms works on constrained devices in different contexts, all our experiments show that ECC is the most suitable security algorithm in IOT contexts.

scholarly journals Shear Strength and Aging Characteristics of Sn-3.0Ag-0.5Cu/Cu Solder Joint Reinforced with ZrO2 Nanoparticles

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1295
Author(s):  
Sri Harini Rajendran ◽  
Seung Jun Hwang ◽  
Jae Pil Jung
Keyword(s):  
Shear Strength ◽  
Solder Joint ◽  
Solder Joints ◽  
Solder Matrix ◽  
Fracture Analysis ◽  
Zro2 Nanoparticles ◽  
Solder Paste ◽  
Lap Shear ◽  
Matrix Fracture ◽  
The Matrix

This study investigates the shear strength and aging characteristics of Sn-3.0Ag-0.5Cu (SAC 305)/Cu joints by the addition of ZrO2 nanoparticles (NPs) having two different particle size: 5–15 nm (ZrO2A) and 70–90 nm (ZrO2B). Nanocomposite pastes were fabricated by mechanically mixing ZrO2 NPs and the solder paste. ZrO2 NPs decreased the β-Sn grain size and Ag3Sn intermetallic compound (IMC) in the matrix and reduced the Cu6Sn5 IMC thickness at the interface of lap shear SAC 305/Cu joints. The effect is pronounced for ZrO2A NPs added solder joint. The solder joints were isothermally aged at 175 °C for 24, 48, 144 and 256 h. NPs decreased the diffusion coefficient from 1.74 × 10–16 m/s to 3.83 × 10–17 m/s and 4.99 × 10–17 m/s for ZrO2A and ZrO2B NPs added SAC 305/Cu joints respectively. The shear strength of the solder joints decreased with the aging time due to an increase in the thickness of interfacial IMC and coarsening of Ag3Sn in the solder. However, higher shear strength exhibited by SAC 305-ZrO2A/Cu joints was attributed to the fine Ag3Sn IMC’s dispersed in the solder matrix. Fracture analysis of SAC 305-ZrO2A/Cu joints displayed mixed solder/IMC mode upon 256 h of aging.

COPPER ALLOY No. 184

Alloy Digest ◽  
1979 ◽  
Vol 28 (4) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Copper Alloy ◽  
Electronic Devices ◽  
Heat Treating ◽  
Age Hardening ◽  
Temperature Performance ◽  
Structural Parts

Abstract Copper Alloy No. 184 combines good strength and hardness with fairly high electrical and thermal conductivity. It is an age-hardening type of alloy that formerly was known as Chromium Copper. Its applications include structural parts, electrode holder jaws and various components for electrical and electronic devices. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-371. Producer or source: Copper and copper alloy mills.

scholarly journals Effect on the wettability, hardness and shear strength properties of 3%-nano Titanium Oxide (TiO2) added Sn-3.8Ag-0.7Cu (SAC)/Copper (Cu) solder joint

2018 ◽  
Vol 237 ◽  
pp. 02013 ◽  
Author(s):  
Amares Singh ◽  
Rajkumar Durairaj
Keyword(s):  
Contact Angle ◽  
Shear Strength ◽  
Solder Alloy ◽  
Electronic Devices ◽  
Strength Properties ◽  
Micro Hardness ◽  
Excellent Performance ◽  
Cu Substrate ◽  
Weight Percentage ◽  
Sac Solder

Demand towards smaller electronic devices prompts the electronic interconnection to have less density and minimal weight percentage and such of this concern tips to applications of nanoparticles incorporation to the solder alloy. In this work, the effect of titanium dioxide (TiO2) nanoparticles (<100nm) additions on the performance of wettability micro hardness, and shear strength of the Sn-3.8Ag-0.7Cu (SAC) solder alloy soldered on the Copper (Cu) substrate was investigated. The SAC added 3% TiO2 nanoparticles had a slight decrease in the micro hardness compared to the plain SAC in this study but the value still surpasses many other common solder alloy’s hardness value. The wettability test was conducted by taking account the contact angle achieved by soldering the SAC added 3% TiO2 solder alloy to the Cu substrate and contact angle produced was less than 40°. As for the shear strength, there was a clear increment of 13% in the shear strength compared to the plain SAC solder alloy. Quite observant, the additions of TiO2 nanoparticles displayed significant influence on these properties that contributes to excellent performance. Much detailed discussion are elaborated in the content below aiding with results and theory behind the result achieved.

scholarly journals Abnormal Shear Performance of Microscale Ball Grid Array Structure Cu/Sn–3.0Ag–0.5Cu/Cu Solder Joints with Increasing Current Density

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Bo Wang ◽  
Wangyun Li ◽  
Kailin Pan
Keyword(s):  
Shear Strength ◽  
Critical Current Density ◽  
Joule Heating ◽  
Current Density ◽  
Solder Joints ◽  
Solder Matrix ◽  
Ball Grid Array ◽  
Current Stressing ◽  
Shear Performance ◽  
Array Structure

The shear performance and fracture behavior of microscale ball grid array structure Cu/Sn–3.0Ag–0.5Cu/Cu solder joints with increasing electric current density (from 1.0 × 103 to 6.0 × 103 A/cm2) at various test temperatures (25 °C, 55 °C, 85 °C, 115 °C, 145 °C, and 175 °C) were investigated systematically. Shear strength increases initially, then decreases with increasing current density at a test temperature of no more than 85 °C; the enhancement effect of current stressing on shear strength decreases and finally diminishes with increasing test temperatures. These changes are mainly due to the counteraction of the athermal effect of current stressing and Joule heating. After decoupling and quantifying the contribution of the athermal effect to the shear strength of solder joints, the results show that the influence of the athermal effect presents a transition from an enhancement state to a deterioration state with increasing current density, and the critical current density for the transition decreases with increasing test temperatures. Joule heating is always in a deterioration state on the shear strength of solder joints, which gradually becomes the dominant factor with increasing test temperatures and current density. In addition, the fracture location changes from the solder matrix to the interface between the solder matrix and the intermetallic compound (IMC) layer (the solder/IMC layer interface) with increasing current density, showing a ductile-to-brittle transition. The interfacial fracture is triggered by current crowding at the groove of the IMC layer and driven by mismatch strain at the solder/IMC layer interface, and the critical current density for the occurrence of interfacial fracture decreases with increasing test temperatures.

Experimental Study on Shear Strength of Root-Soil Composite of Different Grass and Shrub Plants in Three Gorges Reservoir Region

2013 ◽  
Vol 838-841 ◽  
pp. 981-986
Author(s):  
Mo Zhen Hu ◽  
Zhen Yao Xia ◽  
Yue Shu Yang ◽  
Li Deng ◽  
Xiao Pei Xu
Keyword(s):  
Shear Strength ◽  
Cynodon Dactylon ◽  
Plant Root ◽  
Reinforced Soil ◽  
Purple Soil ◽  
Soil Shear Strength ◽  
Plant Root System ◽  
The Relationship ◽  
Root Content ◽  
Peak Value

This paper discusses the relationship between shear strength of soil-root composite and root content of different plant species. The direct shear test of root - soil composite was made by grass and shrub plants -- alfalfa, Indigofera amblyatha, cynodon dactylon and purple soil .That how plant root system can improve the soil shear strength was analyzed. The results show that the shear strength of reinforced soil is increased. When the same plant root-soil composite is under the same root content, the shear strength is enhanced with the increase of normal stress. The peak value of shear strength appears in 0.4 - 0.5g per 60 cubic centimeter.

Shear Test on Mixed Slide-Zone Soils of Landslide under Different Water Content

2011 ◽  
Vol 301-303 ◽  
pp. 1208-1213
Author(s):  
Ting Kai Nian ◽  
Zhong Kai Feng ◽  
Peng Cheng Yu ◽  
Hui Jun Wu
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Water Content ◽  
Strain Softening ◽  
Residual Soil ◽  
Strain Behavior ◽  
Softening Behavior ◽  
Direct Shear Apparatus ◽  
Slide Zone ◽  
Peak Value

This study is based on a typical residual soil landslide adjacent to Daxishan Reservior in Dalian city of China. By drilling the original samples in the field and remodeling the copy samples in the laboratory, a series of geotechnical experiments are carried out by the improved direct shear apparatus to obtain the changing law between the shear strength and water content of the mixed slide-zone soils. Emphasis is given on the shear stress-strain behavior and the corresponding constitutive model under different water content for the soils. Especially, the typical fitting equation is achieved to reflect the state of shear stress-normal stress-water content, some strain softening and hardening behavior on the mixed slide-zone soils of landslide is also discussed in detail. The results indicate that the shear strength is significantly related to water content of mixed slide-zone soils of landslide. The bigger water content of slide-zone soil is, the smaller the shear strength of soils is. When water content of mixed slide-zone soils approaches to certain value (i.e., 15%), the curve of shear stress and displacement shows a remarkable softening behavior, and the shear strength has marked a peak value.

scholarly journals An Empirical Shear Model of Interface Between the Loess and Hipparion Red Clay in a Loess Landslide

2022 ◽  
Vol 9 ◽  
Author(s):  
Yanbo Zhu ◽  
Shuaisheng Miao ◽  
Hongfei Li ◽  
Yutao Han ◽  
Hengxing Lan
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Failure Mode ◽  
Sliding Mode ◽  
Interface Roughness ◽  
Peak Strength ◽  
Contact Interface ◽  
Interface Morphology ◽  
Red Clay ◽  
Shear Model

Quaternary loess is widely distributed over the tertiary Hipparion red clay on the Loess Plateau of China. Large-scale loess landslides often occur along the weak contact interface between these two sediment materials. To investigate the failure mode and shear strength characteristics of the loess–Hipparion red clay contact interface, a series of shearing experiments were performed on interface specimens using purpose-built shear equipment. In this article, the relationship between shear strength and interface morphology is discussed, and an empirical shear model of the interface is proposed based on the experimental results and theoretical work. The results indicate that discontinuities between the loess and the Hipparion red clay reduce the shear strength of specimens significantly. The contribution of the contact interface to shear performance including failure mode, shear deformation, and shear strength varies with the interface morphology and the applied normal stress. With low interface roughness or normal stress, sliding failure is likely to occur. With increasing interface roughness and normal stress, the peak strength increases rapidly. With further increase in the interface roughness and normal stress, the increment of peak strength decreases gradually as the failure mode transitions from sliding mode to cutoff mode. A staged shear model that takes the failure mode into consideration is developed to express the non-linear change in the interface shear strength. The shear model’s capability is validated by comparing model estimates with experimental data. This work improves our understanding of shear mechanisms and the importance of considering the effects of interfacial properties in the mechanical behavior of contact interfaces.

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