Effect of Friction Stir Processing Process Parameters on the Mechanical Properties of AZ31B Mg Alloy (original) (raw)
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The present study investigates the effect of tool shoulder profile on the mechanical properties of friction stir processed AZ31B magnesium alloy The chosen process parameters are tool rotational speed and feed rate. The experiments were conducted with 3 level 2 factors full factorial design with two replications for both the tools. The tensile strength and micro hardness were the responses. The study reveals that, the properties of the materials processed with concave shoulder tool were governed by strain hardening effect. Likewise, the properties of the materials processed with the step shoulder tool were governed by the grain size.
Journal of Manufacturing Processes, 2013
The present study investigates the effect of tool shoulder profile on the mechanical and tribological properties of friction stir processed AZ31B magnesium alloy. The tool rotational speed and feed rate are the chosen process parameters. The experiments were conducted with 3 level 2 factors full factorial design. The recorded responses were tensile strength, wear losses and corrosion rate. The results were analyzed with the help microstructures of the processed samples. The study reveals that, for concave shoulder tool, the strain hardening effect was playing a major role in determining the properties of the processed materials and for the step shoulder tool, the grain size plays a major role in determining the properties of the processed materials.
Influence of Process Parameters on Microstructure of Friction Stir Processed Mg AZ31 Alloy
2014
Friction stir processing (FSP) has been developed on the principles of friction stir welding (FSW) as an effective and efficien new method for grain refinement and microstructural modification, providing intense plastic deformation as well as higher strain rates than other conventional severe plastic deformation methods. FSP produces an equiaxed homogeneous microstructure consisting of fine grains, resulting in the enhancement of the properties of the material at room temperature. The objective of the present paper is to examine the influence of friction stir processing (FSP) parameters namely tool rotational speed (RS), tool traverse speed (TS) and tool tilt angle (TA) on the microstructures of friction stir processed AZ31B-O magnesium alloy. This investigation has focused on the microstructural changes occurred in the dynamically recrystallised nugget zone/ stir zone and the thermo mechanically affected zone during FSP. The results presented in this work indicate that all the thre...
Journal of Mechanical Science and Technology, 2016
In this paper, the effect of heat treatment and number of passes on microstructure and mechanical properties of friction stir processed AZ91C magnesium alloy samples were investigated. From six samples of as-cast AZ91C magnesium alloy, three plates were pre-heated at temperature of 375°C for 3 hours, and then were treated at temperature of 415°C for 18 hours and finally were cooled down in air. Three plates were relinquished without heat treatment. 8 mm thick as-cast AZ91C magnesium alloy plates were friction stir processed at constant traverse speed of 40 mm/min and tool rotation speed of 1250 rpm. After process, microstructural characterization of samples was analyzed using optical microscopy and tensile and Vickers hardness tests were performed. It was found that heat treated samples had finer grains, higher hardness, improved tensile strength and elongation relative to non-heat treated ones. As the number of passes increased, higher UTS and TE were achieved due to finer grains and more dissolution of β phase (Mg 17 Al 12). The micro-hardness characteristics and tensile improvement of the friction stir processed samples depend significantly on grain size, removal of voids and porosities and dissolution of β phase in the stir zone.
Modern Mechanical Engineering, 2017
Friction stir processing (FSP) is an important microstructural alteration process used recently in the engineering field. Grains alteration and hence the mechanical properties of the possessed zone are controlled by the temperature, heating and cooling rate. In this work, AZ31B magnesium samples were friction stir processed in three different cooling conditions like air, water and cryogenic (liquid nitrogen) cooling. 1000 rpm and 60 mm/min were kept constant as tool rotation speed and traverse speed respectively in all the three mediums. The consequence of these conditions on thermal fields, axial force, resulting grain structure and mechanical properties was studied. It is found that the cryogenic treated friction stir processed samples exhibit fine grain structures and hence offer better mechanical properties than the air and water cooled processed samples.
Effect of Friction Stir Processing on AZ91 Mg-alloy: A Review
Jurnal Kejuruteraan
Generally properties of as-cast AZ91 soft Mg-alloy can be improved by conventional artificial aging. Conventional methods are time consuming and expensive process. Friction stir processing (FSP) based on working principle of Friction stir welding can replace the conventional processes at some extent. FSP generates enough heat in process to decrease grain size of coarse grains significantly and accordingly alter the properties. FSP extensive used for modification of morphology, grain refinement etc. and especially for as cast alloys. By performing FSP successfully on AZ91 alloy many properties of as-cast AZ91 can be changed significantly by varying friction stir process parameters. The improved resultant properties of Friction stir processed AZ91 alloys are credited to plastic deformation of alloy sheet by rotating non-consumable tool. Due to plastic deformation number of dislocation increase and it may by pile up, as a result the movement of dislocations are restricted and it requir...
Improving the Tribological Properties of Mg Based AZ31 Alloy Using Friction Stir Processing
Advanced Materials Research, 2012
Materials with improved tribological properties have become the pre-requisite of advanced engineering design. Surface metal matrix composites (SMMCs) exhibit a unified combination of good tribological properties and high toughness of the interior bulk metal when compared with monolithic materials. Friction stir processing, a microstructure modification technique, has emerged as one of the processes used for fabrication of SMMCs. Commercial cast or wrought type Mg–Al–Zn AZ-series alloys, such as AZ91, AZ61 or AZ31 with 3–9 wt.% Al and 1 wt.% Zn, have been widely used in automobiles or electronic appliances. Due to low percentage of alloying elements/second phase elements in these alloys, the grain refinement and hence the mechanical properties such as hardness cannot be appreciably enhanced. In this study, FSP was used to fabricate AZ31 based nanocomposite using TiC as reinforcement. FSP was performed at a fixed volume fraction of TiC under varying cooling conditions. Tribological pe...
OPTIMIZING THE PROCESS PARAMETERS OF FRICTION STIR WELDED JOINT OF MAGNESIUM ALLOY AZ31B
This paper deals with Friction stir welding of AZ31B Mg alloy by using H13 Tool at different rotational speeds and welding speeds .Experiments were conducted according to L4 Orthogonal array which was suggested by Taguchi. Optimum parameters for optimum Tensile strength, Hardness and Ductility were found with the help of S/N ratios. Therefore optimization of input process parameter is required to achieve good quality of welding. In this experiment the effect of process parameters on welded joint was studied and optimizes the parameter by using Taguchi method and stated regression equation for tensile strength and hardness. Assigns the rank to each factor which are having more influence on the mean of tensile strength and hardness.
Effect of Microstructure and Texture on Forming Limits in Friction Stir Processed AZ 31B Mg Alloy
2014
The present work describes the influence of the friction stir processing (FSP) process parameters, namely the tool rotational speed, the tool traverse speed, and the tool tilt angle on the forming-limit strains, the microstructure and the texture of friction stir processed magnesium AZ31B alloy. Limiting dome height tests were carried out at different combinations of process conditions to investigate the forming behavior of FSPed material. It has been found that few combinations of the FSP parameters have resulted in homogeneous microstructure. This has resulted in the larger fracture major strains than that of the base material. An attempt has been made to explain the forming limits of the material with the help of the change in the microstructure and the texture during FSP.
Microstructural Evaluation of Friction Stir Processed AZ31B-H24 Magnesium Alloy
Canadian Metallurgical Quarterly, 2007
The microstructural characteristics in an AZ31B-H24 magnesium alloy after friction stir processing (FSP) were examined. The effects of FSP parameters including forge force and traverse speed on the microstructure were evaluated. It was observed that the grain size increased from about 4 mm in the base metal to about 8 mm at the centre of the stir zone after FSP. The aspect ratio of the grains decreased towards the centre of the stir zone. The changes in the grain size and shape resulted in a drop in micro-indentation hardness from 75 HV in the base metal to about 55 HV at the centre of the stir zone. Increasing the forge force or decreasing the traverse speed increased the grain size due to a greater heat input. It was also observed that the annealing effects (recrystallization and subsequent softening) of FSP were less pronounced with increasing distance horizontally or vertically from the pin tool due to the presence of temperature gradient. Furthermore, the Hall-Petch type relationships between the microhardness and the grain size were found to be valid after FSP.