A Computational Study of Plastic Deformation in AISI 304 Induced by Surface Mechanical Attrition Treatment

2010 ◽  
Author(s):  
X. C. Zhang ◽  
J. Lu ◽  
S. Q. Shi ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
...  
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.


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.


2015 ◽  
Vol 813 ◽  
pp. 307-314
Author(s):  
Hao Jiang ◽  
Qing Wang ◽  
Jian Lu ◽  
Li Min Zhou

Surface Mechanical Attrition Treatment (SMAT) process, as one of the typical severe plastic deformation technologies, can be utilized to generate layup structure with finer size of grains and large residual stresses at the near treated surface area on the alloys. Such technology not only improves the mechanical behaviors but also keeps neatness of alloys without inducing extra compositions. In this paper, four major controllable parameters of SMAT process are investigated to demonstrate their influence on ball-impacting intensity of the treatment, which the improvement of mechanical behaviors are greatly dependent on. The high speed camera is employed to capture the motion of the balls and measure the impact velocities by counting the number of frames. The compared results indicate that the amount of balls not only varies the average velocities during SMAT process, but also offsets the effect of distance between treated surface and source of balls. In addition, the influence of ball sizes, the mentioned distance and power of excitation exhibits apparently on intensity of SMAT process when limited amount of balls are used.


2013 ◽  
Vol 794 ◽  
pp. 238-247 ◽  
Author(s):  
Atul M. Gatey ◽  
Santosh S. Hosmani ◽  
Rajkumar Singh ◽  
Satyam Suwas

Surface mechanical attrition treatment (SMAT) technique has became popular to develop a nanostructured surface layer on metallic materials for upgrading their overall properties and performance. In this paper, we have presented the SMATing behavior of low stacking fault energy material like AISI 304 using optical microscopy, SEM, microhardness measurement and XRD analysis. SMATing was performed for 15, 30, 45, 60, 75, 90 min by using hardened bearing-steel balls (size: 5.7 mm diameter, hardness: 500HV0.1) at 50 Hz vibrating frequency. XRD analysis indicated the lowest grain-size of about 8.6 nm in the surface region of specimen SMATed for 60 min. In comparison with the non-SMATed specimen, 17 times increase in the dislocation density and 4 times increase in the micro-strain were observed in this SMATed specimen. Improvement in the surface-hardness due to the SMAT was almost two times hardness before SMAT was 190 HV0.1 and after SMAT it was 400 HV0.1. There is a gradual decrease in the hardness value across the cross-section of the specimen, and core-hardness value was reached after 300 μm depth below the surface. XRD results indicated the possibility of martensitic phase transformation at the surface during SMATing of AISI 304 steel. SMATed AISI 304 specimens showed good thermal stability at 550°C for 6 h which was confirmed by microhardness measurement


2021 ◽  
Vol 10 (1) ◽  
pp. 101-108
Author(s):  
Pham Quang Trung ◽  
To Dinh Kha

Surface mechanical attrition treatment (SMAT) or ultrasonic shot peening method improves mechanical properties of metallic materials by causing the plastic deformation on their surface layer of the workpiece. In this research, an ultrasonic generator, an ultrasonic booster, a sonotrode, one hundred steel balls with the mean diameter of 1 mm, an optical microscope, an automatic roughness meter, and other supporting accessories are employed to conduct the experiment. The effect of shot peening time of the ultrasonic shot peening method on the surface coverage and the roughness of the treated aluminum sample A7075 is systematically investigated. The study reveals that shot peening time has a significant effect on the coverage and the surface roughness of the treated samples. The surface of sample is rougher with the increasing of shot peening time and the surface is full coverage after shot peening in 35s. The results of this study indicate that the method of surface mechanical attrition (SMAT) or ultrasonic shot peening is an effective method to induce the plastic deformation on the material. It also shows that this is a promising method to investigate the effects of experimental parameters on the microstructure, properties, and fatigue life of the material.


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