A Viscoplastic Constitutive Model for 63Sn37Pb Eutectic Solders

2002 ◽  
Vol 124 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Sung Yi ◽  
Guangxing Luo ◽  
Kerm Sin Chian
Keyword(s):  
Grain Boundary ◽  
Constitutive Model ◽  
Tensile Test ◽  
Present Model ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Tensile Creep ◽  
Grain Sizes ◽  
Boundary Sliding ◽  
Matrix Dislocation

In the present study, a new constitutive model for eutectic solders (63Sn37Pb) is proposed. Grain sizes and phase sizes are considered as the coarsening is one of the main reasons for failure of solder joints. The present model has been developed based on the combination of grain boundary sliding and matrix dislocation deformation mechanisms in order to describe a thermo-mechanical behavior of eutectic solders. Internal stress tensors are also introduced to describe the transient behaviors during the tensile test and first stage creep. A series of tensile, creep, and creep recover tests were conducted at temperature range from −10 to 100°C. The specimens with two different phase sizes were tested. Good agreements were obtained between the experimental results and the model.

Structure Evolution and Deformation Mechanisms in Ultrafine-Grained Aluminum under Tension at Room Temperature

2010 ◽  
Vol 667-669 ◽  
pp. 915-920
Author(s):  
Konstantin Ivanov ◽  
Evgeny V. Naydenkin
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Structure Evolution ◽  
Dislocation Slip ◽  
Polished Surface ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Boundary Sliding

Deformation mechanisms occurring by tension of ultrafine-grained aluminum processed by equal-channel angular pressing at room temperature are investigated using comparative study of the microstructure before and after tensile testing as well as deformation relief on the pre-polished surface of the sample tested. Deformation behavior and structure evolution during tension suggest development of grain boundary sliding in addition to intragrain dislocation slip. Contribution grain boundary sliding to the overall deformation calculated using the magnitude of shift of grains relative to each other is found to be ~40%.

Temperature Dependence of Compressive Deformation Behavior of Mg89Zn4Y7 Extruded LPSO-Phase Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 607-610 ◽  
Author(s):  
Koji Hagihara ◽  
Akihito Kinoshita ◽  
Yuya Sugino ◽  
Michiaki Yamasaki ◽  
Yoshihito Kawamura ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Deformation Behavior ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Petch Relationship ◽  
Lpso Phase ◽  
Boundary Sliding

Deformation mechanisms of Mg89Zn4Y7 (at.%) extruded alloy, which is mostly composed of LPSO-phase, was investigated focusing on their temperature dependence. The yield stress of as-extruded alloy showed extremely high value of ~480 MPa at RT, but it largely decreased to ~130 MPa at 300 °C. The decreasing rate of the yield stress could be significantly reduced, however, by the annealing of specimen at 400 °C, by suppressing the microyielding which is considered to occur related by the grain boundary sliding in restricted regions. The yield stress of the annealed specimens with random textures could be estimated by the Hall-Petch relationship by regarding the length of long-axis of plate-like grains as a grain size between RT and 300 °C. The yield stress of the annealed specimens maintained high values even at 200°C, but it also showed large decreases at 300 °C.

Analysis of Creep Deformation Due to Grain-Boundary Diffusion/Sliding

2007 ◽  
Vol 345-346 ◽  
pp. 565-568
Author(s):  
Byung Nam Kim ◽  
Keijiro Hiraga ◽  
Koji Morita ◽  
Hidehiro Yoshida
Keyword(s):  
Grain Size ◽  
Creep Rate ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Effective Diffusion ◽  
High Viscosity ◽  
Grain Boundary Sliding ◽  
Grain Boundary Diffusion ◽  
Grain Sizes ◽  
Boundary Sliding

For steady-state deformation caused by grain-boundary diffusion and viscous grain-boundary sliding, the creep rate of regular polyhedral grains is analyzed by the energy-balance method. For the microstructure, the grain-grain interaction increases the degree of symmetry of diffusional field, resulting in a decrease of the effective diffusion distance. Meanwhile, the viscous grain-boundary sliding is found to decrease the creep rate. The present analysis reveals that the grain-size exponent is dependent on the grain size and the grain-boundary viscosity: the exponent becomes unity for small grain sizes and/or high viscosity, while it is three for large grain sizes and/or low viscosity.

Features of Work Hardening of Polycrystals with Nanograins

2008 ◽  
Vol 584-586 ◽  
pp. 35-40 ◽  
Author(s):  
Eduard Kozlov ◽  
Nina Koneva ◽  
L.I. Trishkina ◽  
A.N. Zhdanov ◽  
M.V. Fedorischeva
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Work Hardening ◽  
Mechanical Characteristics ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Grain Sizes ◽  
Boundary Sliding ◽  
Size Interval

The present work is devoted to the investigation of the influence of the grain size on the main mechanical characteristics of nanopolycrystals of different metals. The Hall-Petch parameter behaviour for Al, Cu, Ni, Ti and Fe was examined in the wide grain size interval. The stages of plastic deformation and the parameters of work hardening for nanocrystalline copper were analysed in detail. The deformation mechanisms and critical grain sizes accounting for the transition from the dislocation slip to the grain boundary sliding were described.

A Multiple-Mechanism-Based Model for Prediction of Yield Strength in Bicrystals

2016 ◽  
Vol 08 (04) ◽  
pp. 1650046
Author(s):  
Gan-Yun Huang ◽  
Xiang-Long Peng
Keyword(s):  
Yield Strength ◽  
Grain Boundary ◽  
Present Model ◽  
Grain Boundary Sliding ◽  
Dislocation Emission ◽  
Gradient Effect ◽  
Multiple Mechanism ◽  
Polycrystal Plasticity ◽  
Pile Up ◽  
Boundary Sliding

Different mechanisms such as glide of lattice dislocation and grain boundary mediated processes may be active during the plastic deformation of polycrystals with small grain size. A continuum model for polycrystal plasticity has been developed to capture such a feature. Specifically, the strain gradient effect due to dislocation pile-up, dislocation emission/absorption at surface and grain boundary sliding have been taken into account from the perspective of energy storage. As an application of the model, a bicrystal under plane constrained shear has been considered. The dependence of yield strength on the thickness of the bicrystal has been investigated. It has been demonstrated the present model predicts the yield strength of the bicrystal first increases and then decrease with decrease in the thickness, which is similar to the inverse Hall–Petch behavior but with a different scaling. Such behavior is attributed to the transition in different dominant deformation mechanisms at different values of the thickness.

scholarly journals A microstructure sensitive grain boundary sliding and slip based constitutive model for machining of Ti-6Al-4V

2017 ◽  
Vol 109 ◽  
pp. 67-81 ◽  
Author(s):  
Patxi Fernandez-Zelaia ◽  
Shreyes Melkote ◽  
Troy Marusich ◽  
Shuji Usui
Keyword(s):  
Grain Boundary ◽  
Constitutive Model ◽  
Grain Boundary Sliding ◽  
Boundary Sliding
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