A constitutive model of nanocrystalline metals based on competing grain boundary and grain interior deformation mechanisms

2011 ◽  
Vol 65 (23-24) ◽  
pp. 3391-3395 ◽  
Author(s):  
Ercan Gürses ◽  
Tamer El Sayed
Keyword(s):  
Grain Boundary ◽  
Constitutive Model ◽  
Deformation Mechanisms ◽  
Nanocrystalline Metals

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.

scholarly journals Constitutive Description of Extra Strengthening in Gradient Nanotwinned Metals

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2375
Author(s):  
Wufan Chen ◽  
Panpan Wan ◽  
Qingkun Zhao ◽  
Haofei Zhou
Keyword(s):  
Constitutive Model ◽  
Structural Design ◽  
Work Hardening ◽  
Mechanical Response ◽  
Theoretical Framework ◽  
Deformation Mechanisms ◽  
Strengthening Effect ◽  
Metallic Materials ◽  
Engineering Applications ◽  
Increased Strength

Gradient nanotwinned (GNT) metals exhibit extra strengthening and work hardening behaviors, which endow them impressive potentials in engineering applications. The increased strength is attributed to the dense interactions between dislocations and boundaries in the grain interiors. However, a constitutive model elucidating the extra strengthening effect is currently lacking. Here, we propose a theoretical framework to describe the mechanical response of GNT metals, especially the unusual extra strengthening behavior. The model captures the deformation mechanisms of GNT metals and coincides well with the reported experiment. The constitutive description developed in this work presents a tool to guide the structural design for developing gradient metallic materials.

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.

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