A Damage-Coupled Time-Dependent Multi-Axial Fatigue Failure Model for Solder Alloy 63Sn-37Pb

2011 ◽  
Vol 128-129 ◽  
pp. 361-366
Author(s):  
Yan Luo ◽  
Qing Gao

Based on the time-dependent deformation behavior of solder alloy 63Sn-37Pb at room temperature, a damage-coupled unified visco-plastic multi-axial fatigue model and its failure criterion were proposed. In the evolution equation of damage for the model, the time-dependent effect of damage was taken into account. The model was used to predict the fatigue life under different loading paths. The comparison between the predicted and experimental results demonstrated that the time-dependent failure model can simulate the deformation behavior and predict the fatigue life well under different nonproportional strain paths.

2006 ◽  
Vol 129 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Xianjie Yang ◽  
Yan Luo ◽  
Qing Gao

Based on the time dependent multiaxial deformation behavior of 96.5Sn-3.5Ag solder alloy, a constitutive model is proposed which considers the nonproportional multiaxial cyclic deformation properties. In the back stress evolution equations of this model, the nonproportionality which affects the back stress evolution rate is introduced. The approach for the determination of model parameters is proposed. The model is used to describe the time-dependent cyclic deformation behavior of 96.5Sn-3.5Ag solder alloy under cross, rectangular, rhombic, and double-triangular tensile–torsion multiaxial strain paths at different strain rates with different dwell time. The comparison between the predicted and experimental results demonstrates that the model can satisfactorily describe the time-dependent multiaxial cyclic deformation behavior under complicated nonproportional cyclic straining.


1996 ◽  
Vol 460 ◽  
Author(s):  
D. B. Hanes ◽  
R. Gibala

ABSTRACTThe monotonie mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonie testing.


1987 ◽  
Vol 108 ◽  
Author(s):  
Ravichandran Subrahmanyan ◽  
Donald Stone ◽  
Che-Yu Li

ABSTRACTRoom temperature deformation data of leadless solder joints are reported. The joints were sheared under cyclic, displacement controlled loading at frequencies between 0.001 and 0.01 Hz. A microplastic model was utilized to simulate the stress-strain loops, which demonstrated a pronounced Bauschinger effect. The implications of microplasticity on fatigue life of solder joints are discussed. This phenomenon must be taken into account in an accurate prediction of solder deformation at low strain ranges.


Author(s):  
Shrikant P. Bhat

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).


2021 ◽  
Author(s):  
Jian Qu ◽  
Xin Zhang ◽  
Zhong-Jie Wang ◽  
Shuyan Zhang ◽  
Yejian Yu ◽  
...  

Time-dependent evolutive afterglow materials can increase the security level by providing additional encryption modes in anti-counterfeiting and data encryption. The design of carbon-based materials with dynamic afterglow colors is attractive...


2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744014
Author(s):  
M. Li ◽  
Q. W. Jiang

Tensile deformation behavior of ultrafine-grained (UFG) copper processed by accumulative roll-bonding (ARB) was studied under different strain rates at room temperature. It was found that the UFG copper under the strain rate of 10[Formula: see text] s[Formula: see text] led to a higher strength (higher flow stress level), flow stability (higher stress hardening rate) and fracture elongation. In the fracture surface of the sample appeared a large number of cleavage steps under the strain rate of 10[Formula: see text] s[Formula: see text], indicating a typical brittle fracture mode. When the strain rate is 10[Formula: see text] or 10[Formula: see text] s[Formula: see text], a great amount of dimples with few cleavage steps were observed, showing a transition from brittle to plastic deformation with increasing strain rate.


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