A Numerical Investigation of a Single-Shot Impact Effects on Plastic Deformation of Titanium Alloys

2021 ◽  
Vol 105 ◽  
pp. 119-124
Author(s):  
Eser Yarar ◽  
A. Tamer Erturk

Surface mechanical attrition treatment is a pre-stressing process that enhances the lifespan of mechanical parts. The experimental evaluation of SMAT parameters is not only very complex but also costly. In this study, the single impact behavior of commercially pure titanium and Ti6Al4V alloys is analyzed using the finite element method. For simulating the single-shot impact process, a rigid sphere on a rectangular component is modeled using ANSYS/AUTODYN explicit dynamic solver. The effects of single-shot impact on the induced compressive residual stress and plastic deformation were investigated. Besides, the change in shot velocity after a single shot was revealed by calculating the restitution coefficient, and its relation to plastic deformation was investigated.

Author(s):  
Saurabh Basu ◽  
Zhiyu Wang ◽  
Christopher Saldana

Comprehensive understanding of thermomechanical response and microstructure evolution during surface severe plastic deformation (S 2 PD) is important towards establishing controllable processing frameworks. In this study, the evolution of crystallographic textures during directional surface mechanical attrition treatment on copper was studied and modelled using the visco-plastic self-consistent framework. In situ high-speed imaging and digital image correlation of surface deformation in circular indentation were employed to elucidate mechanics occurring in a unit process deformation and to calibrate texture model parameters. Material response during directional surface mechanical attrition was simulated using a finite-element model coupled with the calibrated texture model. The crystallographic textures developed during S 2 PD were observed to be similar to those resultant from uniaxial compression. The implications of these results towards facilitating a processing-based framework to predict deformation mechanics and resulting crystallographic texture in S 2 PD configurations are briefly discussed.


2011 ◽  
Vol 675-677 ◽  
pp. 239-242
Author(s):  
Chun Huan Chen ◽  
Cheng Jin ◽  
Rui Ming Ren

The effect of the strain rate on the surface nanocrystallization of titanium is investigated both theoretically and experimentally in this paper. The strain rate variation and stress distribution from surface to the interior of titanium during shot peening are estimated firstly using finite element method. Then shot peening experiment is carried out on a commercially pure titanium (CP-Ti) plate, and the obtained surface microstructures is characterized by transmission electron microscopy (TEM). Combining theoretical simulations and experimental observations, the effect of strain rate on the strain accommodation mechanism and plastic deformation mode are discussed. It is concluded that the strain rate and stress achieve the highest at the top surface layer of CP-Ti, and the strain rate decrease dramatically from the surface to the interior. The strain rate at the top surface layer is up to 104 s-1, which leads to superplastic deformation of Ti. There is no mechanical twin in the surface layer, instead, deformation lamella and adiabatic shear bands are the dominating microstructures. By means of rotation recrystallization, those deformation bands evolve to nanocrystallines.


2010 ◽  
Vol 442 ◽  
pp. 152-157 ◽  
Author(s):  
M. Mansoor ◽  
J. Lu

In the domain of incremental nanotechnology, surface mechanical attrition treatment is a technique which can transform superficial structure of a material to nanocrystalline without changing the chemical composition. This study is a part of the development and implementation of the technique by using ultrasonic vibrations. The material used is pure titanium in rolled and annealed condition. The nanocrystalline structure is characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM). The measured grain size is in the order of 5~60 nm. A correlation in the results of XRD and TEM is also discussed.


2011 ◽  
Vol 66-68 ◽  
pp. 1500-1504 ◽  
Author(s):  
Ming Wen ◽  
Cui'e Wen ◽  
Peter D. Hodgson ◽  
Yun Cang Li

A nanocrystalline (NC) layer with the thickness of 30 µm was produced on pure titanium surface by surface mechanical attrition treatment (SMAT). Microstructure observation indicated that the grain size increases with depth from the treated surface. The friction coefficient decreases and the wear resistance increases with the SMAT sample as compared to its coarse-grained counterpart. The improvement of the wear properties could be attributed to the higher hardness of SMAT sample.


2022 ◽  
Vol 905 ◽  
pp. 3-8
Author(s):  
Eser Yarar ◽  
Alpay Tamer Erturk

Surface mechanical attrition treatment enhances the mechanical properties of metallic materials by inducing high strength layer on the top surface. In this study, multiple-shot impact behavior was modeled for the 7075-T6 aluminum alloy to achieve maximum magnitudes of equivalent stress, plastic strain, residual stress depth, and residual stress. Finite element simulations have been carried out to investigate the effect of selected framework on stress and strains in constituent. The plastic deformation process during SMAT was analyzed using ANSYS/AUTODYN explicit dynamic solver according to shot velocity and diameter with a dynamic explicit finite element method (FEM). Deformation behavior was evaluated after multiple-shot impact.


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