Shear strength and fracture mechanism for full Cu-Sn IMCs solder joints with different Cu3Sn proportion and joints with conventional interfacial structure in electronic packaging

2019 ◽  
Vol 31 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Peng Yao ◽  
Xiaoyan Li ◽  
Xu Han ◽  
Liufeng Xu
Keyword(s):  
Shear Strength ◽  
Cleavage Fracture ◽  
Electronic Packaging ◽  
Fracture Mechanism ◽  
Sandwich Structure ◽  
Fracture Morphology ◽  
Interfacial Structure ◽  
Transgranular Fracture ◽  
Content Type ◽  
Interfacial Delamination

Purpose This study aims to analyze the shear strength and fracture mechanism of full Cu-Sn IMCs joints with different Cu3Sn proportion and joints with the conventional interfacial structure in electronic packaging. Design/methodology/approach The Cu-Sn IMCs joints with different Cu3Sn proportion were fabricated through soldering Cu-6 μm Sn-Cu sandwich structure under the extended soldering time and suitable pressure. The joints of conventional interfacial structure were fabricated through soldering Cu-100 μm Sn-Cu sandwich structure. After the shear test was conducted, the fracture mechanism of different joints was studied through observing the cross-sectional fracture morphology and top-view fracture morphology of sheared joints. Findings The strength of joints with the conventional interfacial structure was 26.6 MPa, while the strength of full Cu-Sn IMCs joints with 46.7, 60.6, 76.7 and 100 per cent Cu3Sn was, respectively, 33.5, 39.7, 45.7 and 57.9 MPa. The detailed reason for the strength of joints showing such regularity was proposed. For the joint of conventional interfacial structure, the microvoids accumulation fracture happened within the Sn solder. However, for the full Cu-Sn IMCs joint with 46.7 per cent Cu3Sn, the cleavage fracture happened within the Cu6Sn5. As the Cu3Sn proportion increased to 60.6 per cent, the inter-granular fracture, which resulted in the interfacial delamination of Cu3Sn and Cu6Sn5, occurred along the Cu3Sn/Cu6Sn5 interface, while the cleavage fracture happened within the Cu6Sn5. Then, with the Cu3Sn proportion increasing to 76.7 per cent, the cleavage fracture happened within the Cu6Sn5, while the transgranular fracture happened within the Cu3Sn. The inter-granular fracture, which led to the interfacial delamination of Cu3Sn and Cu, happened along the Cu/Cu3Sn interface. For the full Cu3Sn joint, the cleavage fracture happened within the Cu3Sn. Originality/value The shear strength and fracture mechanism of full Cu-Sn IMCs joints was systematically studied. A direct comparison regarding the shear strength and fracture mechanism between the full Cu-Sn IMCs joints and joints with the conventional interfacial structure was conducted.

Effects of Sn-Ag-x leveling layers on the microstructure and mechanical properties of SnBi low-temperature solder joints

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yang Liu ◽  
Yuxiong Xue ◽  
Min Zhou ◽  
Rongxing Cao ◽  
Xianghua Zeng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Low Temperature ◽  
Solder Joint ◽  
Design Methodology ◽  
Solder Joints ◽  
Fracture Morphology ◽  
Content Type ◽  
Before And After ◽  
Mechanical Performances

Purpose The purpose of this paper is to investigate the effects of Sn-Ag-x leveling layers on the mechanical properties of SnBi solder joints. Four Sn-Ag-x (Sn-3.0Ag-0.5Cu, Sn-0.3Ag-0.7Cu, Sn-0.3Ag-0.7Cu-0.5 Bi-0.05Ni and Sn-3.0Ag-3.0 Bi-3.0In) leveling layers were coated on Cu pads to prepare SnBi/Sn-Ag-x/Cu solder joints. The microstructure, hardness, shear strength and fracture morphology of solder joints before and after aging were studied. Design/methodology/approach The interfacial brittleness of the SnBi low-temperature solder joint is a key problem affecting its reliability. The purpose of this study is to improve the mechanical properties of the SnBi solder joint. Findings Owing to the addition of the leveling layers, the grain size of the ß-Sn phase in the SnBi/Sn-Ag-x/Cu solder joint is significantly larger than that in the SnBi/Cu eutectic solder joint. Meanwhile, the hardness of the solder bulk in the SnBi/Cu solder joint shows a decrease trend because of the addition of the leveling layers. The SnBi/Cu solder joint shows obvious strength drop and interfacial brittle fracture after aging. Through the addition of the Sn-Ag-x layers, the brittle failure caused by aging is effectively suppressed. In addition, the Sn-Ag-x leveling layers improve the shear strength of the SnBi/Cu solder joint after aging. Among them, the SnBi/SACBN/Cu solder joint shows the highest shear strength. Originality/value This work suppresses the interfacial brittleness of the SnBi/Cu solder joint after isothermal aging by adding Sn-Ag-x leveling layers on the Cu pads. It provides a way to improve the mechanical performances of the SnBi solder joint.

scholarly journals The Interface Microstructure and Shear Strength of Sn2.5Ag0.7Cu0.1RExNi/Cu Solder Joints under Thermal-Cycle Loading

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 518 ◽  
Author(s):  
Congcong Cao ◽  
Keke Zhang ◽  
Baojin Shi ◽  
Huigai Wang ◽  
Di Zhao ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fracture Mechanism ◽  
Thermal Cycle ◽  
Solder Joints ◽  
Joint Interface ◽  
Interface Microstructure ◽  
Average Thickness ◽  
Thermal Cycles ◽  
Initial State ◽  
Cycle Loading

The interface microstructure and shear strength of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal-cycle loading were investigated with scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and physical and chemical tests. The results show that an intermetallic compound (IMC) layer of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints evolved gradually from the scalloped into larger wavy forms with increasing number of thermal cycles. The roughness and average thickness of IMC increased with thermal-cycle loading. However, at longer thermal-cycle loading, the shear strength of the joints was reduced by about 40%. The fracture pathway of solder joints was initiated in the solder seam with ductile fracture mechanism and propagated to the solder seam/IMC layer with ductile-brittle mixed-type fracture mechanism, when the number of thermal cycles increased from 100 to 500 cycles. By adding 0.05 wt.% Ni, the growth of the joint interface IMC could be controlled, and the roughness and average thickness of the interfacial IMC layer reduced. As a result, the shear strength of joints is higher than those without Ni. When compared to joint without Ni, the roughness and average thickness of 0.05 wt.% Ni solder joint interface IMC layer reached the minimum after 500 thermal cycles. The shear strength of that joint was reduced to a minimum of 36.4% of the initial state, to a value of 18.2 MPa.

Numerical analysis of the shear strength of circular reinforced concrete columns subjected to cyclic lateral loads using linear genetic programming

2020 ◽  
Vol 37 (7) ◽  
pp. 2517-2537
Author(s):  
Mostafa Rezvani Sharif ◽  
Seyed Mohammad Reza Sadri Tabaei Zavareh
Keyword(s):  
Numerical Modeling ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Genetic Programming ◽  
Linear Genetic Programming ◽  
Rc Columns ◽  
Content Type ◽  
Alternative Approach ◽  
Engineering Problems

Purpose The shear strength of reinforced concrete (RC) columns under cyclic lateral loading is a crucial concern, particularly, in the seismic design of RC structures. Considering the costly procedure of testing methods for measuring the real value of the shear strength factor and the existence of several parameters impacting the system behavior, numerical modeling techniques have been very much appreciated by engineers and researchers. This study aims to propose a new model for estimation of the shear strength of cyclically loaded circular RC columns through a robust computational intelligence approach, namely, linear genetic programming (LGP). Design/methodology/approach LGP is a data-driven self-adaptive algorithm recently used for classification, pattern recognition and numerical modeling of engineering problems. A reliable database consisting of 64 experimental data is collected for the development of shear strength LGP models here. The obtained models are evaluated from both engineering and accuracy perspectives by means of several indicators and supplementary studies and the optimal model is presented for further purposes. Additionally, the capability of LGP is examined to be used as an alternative approach for the numerical analysis of engineering problems. Findings A new predictive model is proposed for the estimation of the shear strength of cyclically loaded circular RC columns using the LGP approach. To demonstrate the capability of the proposed model, the analysis results are compared to those obtained by some well-known models recommended in the existing literature. The results confirm the potential of the LGP approach for numerical analysis of engineering problems in addition to the fact that the obtained LGP model outperforms existing models in estimation and predictability. Originality/value This paper mainly represents the capability of the LGP approach as a robust alternative approach among existing analytical and numerical methods for modeling and analysis of relevant engineering approximation and estimation problems. The authors are confident that the shear strength model proposed can be used for design and pre-design aims. The authors also declare that they have no conflict of interest.

Fracture Morphology and Residual Stresses of TiAl-Based Alloys Sheet Fabricated by EB-PVD

2006 ◽  
Vol 324-325 ◽  
pp. 307-310
Author(s):  
De Ming Zhang ◽  
Gui Qing Chen ◽  
Chun Mei Zhang ◽  
Jie Cai Han
Keyword(s):  
Free Surface ◽  
Numerical Calculation ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Intergranular Fracture ◽  
Cleavage Fracture ◽  
Vacuum Annealing ◽  
Fracture Morphology ◽  
Columnar Crystal ◽  
X Ray

The TiAl-based alloys sheet with 150 mm × 100 mm × 0.4 mm was fabricated successfully by using EB-PVD method. The fracture morphology and residual stresses of the sheet were analyzed by SEM, numerical calculation and X-ray stress analyzer. The results indicate that before stripping, the depositional layers have a higher compressive stress, and the substrate has a very lower tensile stress. For the isolated TiAl-based alloys sheet, the microstructure of as-deposited sheet is columnar crystal, and the residual stresses distribution on the free surface has a trend that its magnitude decreased gradually from center to edges. After vacuum annealing at 1273 K for 16 h, the columnar crystal transforms into the equiaxed, the residual stresses on the free surface are eliminated ultimately, and the fracture of the material is diverted from the manner of intergranular fracture to the mixed manner of intergranular fracture with cleavage fracture.

Shear strength and temperature distribution model of friction spot lap joint of high density polyethylene with aluminum alloy 7075

2019 ◽  
Vol 10 (4) ◽  
pp. 469-483 ◽  
Author(s):  
Isam Tareq Abdullah ◽  
Sabah Khammass Hussein
Keyword(s):  
Shear Strength ◽  
Temperature Distribution ◽  
High Density Polyethylene ◽  
Contact Region ◽  
High Density ◽  
Distribution Model ◽  
Lap Joint ◽  
Content Type ◽  
Rotating Speed ◽  
Model Of Friction

Purpose The purpose of this paper is to join a sheet of the AA7075 with the high-density polyethylene (HDPE) by a lap joint using friction spot processing and investigate the temperature distribution of joint during this process using the finite element method (FEM). Design/methodology/approach A semi-conical hole was manufactured in the AA7075 specimen and a lap joint configuration was prepared with the HDPE specimen. A rotating tool was used to generate the required heat to melt the polymer by the friction with the AA7075 specimen. The applied tool force moved the molten polymer through the hole. Four parameters were used: lower diameter of hole, rotating speed, plunging depth and time. The results of shear test were analyzed using the Taguchi method. A FEM was presented to estimate the temperature distribution of joint during the process. Findings All specimens failed by shearing the polymer at the lap joint region without dislocation. The specimens of the smallest diameter exhibited the highest shear strength at the lap joint. The maximum ranges of temperature were recorded at the contact region between the rotating tool and the AA7075 specimen. The tool plunging depth recorded the highest effect on the generated heat compared with the rotating speed and plunging time. Originality/value For the first time, the AA7075 sheet was joined with the HDPE sheet by friction spot processing. The temperature distribution of this joint was simulated using the FEM.

Effect of intermetallic compound layer thickness on the shear strength of 1206 chip resistor solder joint

2015 ◽  
Vol 27 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Peter K. Bernasko ◽  
Sabuj Mallik ◽  
G. Takyi
Keyword(s):  
Shear Strength ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Layer Thickness ◽  
Solder Joints ◽  
Ageing Time ◽  
Circuit Board ◽  
Intermetallic Compound Layer ◽  
Content Type ◽  
Surface Mount

Purpose – The purpose of this paper is to study the effect of intermetallic compound (IMC) layer thickness on the shear strength of surface-mount component 1206 chip resistor solder joints. Design/methodology/approach – To evaluate the shear strength and IMC thickness of the 1206 chip resistor solder joints, the test vehicles were conventionally reflowed for 480 seconds at a peak temperature of 240°C at different isothermal ageing times of 100, 200 and 300 hours. A cross-sectional study was conducted on the reflowed and aged 1206 chip resistor solder joints. The shear strength of the solder joints aged at 100, 200 and 300 hours was measured using a shear tester (Dage-4000PXY bond tester). Findings – It was found that the growth of IMC layer thickness increases as the ageing time increases at a constant temperature of 175°C, which resulted in a reduction of solder joint strength due to its brittle nature. It was also found that the shear strength of the reflowed 1206 chip resistor solder joint was higher than the aged joints. Moreover, it was revealed that the shear strength of the 1206 resistor solder joints aged at 100, 200 and 300 hours was influenced by the ageing reaction times. The results also indicate that an increase in ageing time and temperature does not have much influence on the formation and growth of Kirkendall voids. Research limitations/implications – A proper correlation between shear strength and fracture mode is required. Practical implications – The IMC thickness can be used to predict the shear strength of the component/printed circuit board pad solder joint. Originality/value – The shear strength of the 1206 chip resistor solder joint is a function of ageing time and temperature (°C). Therefore, it is vital to consider the shear strength of the surface-mount chip component in high-temperature electronics.

A physical investigation of dimensional and mechanical characteristics of 3D printed nut and bolt for industrial applications

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ramesh Chand ◽  
Vishal S. Sharma ◽  
Rajeev Trehan ◽  
Munish Kumar Gupta
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
3D Printing ◽  
Surface Properties ◽  
3D Printer ◽  
Content Type ◽  
Safety Issues ◽  
Machine Failure ◽  
Sharp Edges ◽  
3D Printed

Purpose A nut bolt joint is a primary device that connects mechanical components. The vibrations cause bolted joints to self-loosen. Created by motors and engines, leading to machine failure, and there may be severe safety issues. All the safety issues and self-loosen are directly and indirectly the functions of the accuracy and precision of the fabricated nut and bolt. Recent advancements in three-dimensional (3D) printing technologies now allow for the production of intricate components. These may be used technologies such as 3D printed bolts to create fasteners. This paper aims to investigate dimensional precision, surface properties, mechanical properties and scanning electron microscope (SEM) of the component fabricated using a multi-jet 3D printer. Design/methodology/approach Multi-jet-based 3D printed nut-bolt is evaluated in this paper. More specifically, liquid polymer-based nut-bolt is fabricated in sections 1, 2 and 3 of the base plate. Five nuts and bolts are fabricated in these three sections. Findings Dimensional inquiry (bolt dimension, general dimensions’ density and surface roughness) and mechanical testing (shear strength of nut and bolt) were carried out throughout the study. According to the ISO 2768 requirements for the General Tolerances Grade, the nut and bolt’s dimensional examination (variation in bolt dimension, general dimensions) is within the tolerance grades. As a result, the multi-jet 3D printing (MJP)-based 3D printer described above may be used for commercial production. In terms of mechanical qualities, when the component placement moves from Sections 1 to 3, the density of the manufactured part decreases by 0.292% (percent) and the shear strength of the nut and bolt decreases by 30%. According to the SEM examination, the density of the River markings, sharp edges, holes and sharp edges increased from Sections 1 to 3, which supports the findings mentioned above. Originality/value Hence, this work enlightens the aspects causing time lag during the 3D printing in MJP. It causes variation in the dimensional deviation, surface properties and mechanical properties of the fabricated part, which needs to be explored.

Residual shear capacity of cold-formed steel-to-sheathing screwed connections at elevated temperatures

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kun Liu ◽  
Wei Chen ◽  
Jihong Ye ◽  
Jian Jiang ◽  
Wenwen Chen ◽  
...  
Keyword(s):  
Shear Strength ◽  
Elevated Temperatures ◽  
Input Parameter ◽  
Single Layer ◽  
Shear Capacity ◽  
Base Layer ◽  
Residual Shear Strength ◽  
Content Type ◽  
Cold Formed Steel ◽  
Fire Conditions

Purpose Most previous thermal-mechanical modeling of cold-formed steel (CFS) walls did not consider the failure of screwed connections under fire conditions because of the limited data of such connections at elevated temperatures. Design/methodology/approach In this study, 285 steady-state tests are conducted on CFS screwed connections with single-layer gypsum plasterboard (GPB) and Bolivian magnesium board (BMB) sheathing at ambient and elevated temperatures. The failure of these connections is described as the breaking of the loaded sheathing edge. Findings For the BMB sheathing screwed connections, hydrochloric acid gas is generated and released above 300°C, and the shear strength becomes much less than that of the GPB sheathing screwed connection above 370°C. Hence, BMB may not be suitable for use as the face-layer sheathing of CFS walls but is still recommended to replace GPB as the base-layer sheathing. The major influencing parameters on the shear strength of screwed connections are identified as the type of sheathing material and the loaded sheathing edge distance. Originality/value Based on the previous and present test results, a unified expression for the residual shear strength of screwed connections with GPB and BMB is proposed at ambient and elevated temperatures with acceptable accuracy. It can be used as the basic input parameter of the numerical simulation of the CFS structures under fire conditions.

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