scholarly journals Role of enhanced surface grain refinement and hardness improvement induced by the combined effect of friction stir processing and ultrasonic impact treatment on slurry abrasive wear performance of silicon carbide particle reinforced A356 composites

Author(s):  
Gökçe Mehmet Gençer ◽  
Fatih Kahraman ◽  
Coşkun Yolcu

Abstract In this study, the slurry abrasive wear behavior of silicon carbide particle reinforced A356 composite alloy was investigated after the different surface mechanical attrition treatments. It is known that the aluminum matrix composites produced by the stir casting method have some deficiencies (e.g unfavorable microstructure formation, particle clustering, porosity formation, etc.). These kinds of drawbacks of the composites adversely affect the surface mechanical properties of materials such as wear resistance. For this purpose, the surface properties of the silicon carbide reinforced A356 matrix composites fabricated through the stir casting method were improved by using friction stir processing (FSP) and ultrasonic impact treatment (UIT) in the study. The results indicated that a remarkable increase was observed in the hardness and wear resistance of the cast composite via FSP and ultrasonic impact treatment following friction stir processing (FSP+UIT). The hardness of the stir zone after FSP and FSP+UIT was determined as 82.7+-2 HV and 101.9 +-3 HV0.2, respectively. The stir zone showed a similar tendency also in slurry abrasive wear resistance. FSP increased the wear resistance in the stir zone at the rate of 33.9% while it was determined as 35.5% for FSP+UIT. The microstructural modification of the cast composite that occurred after FSP was clearly demonstrated via optical microscope and scanning electron microscopy (SEM) examinations. Enhanced grain refinement after FSP+UIT was indicated especially by X-ray diffraction analysis (XRD). According to the findings, it was observed that the application of ultrasonic impact treatment following the friction stir processing can be used to obtain an enhanced microstructure and extra hardness increment in the surface of the SiC reinforced A356 alloy, thus resulting in slurry abrasive wear resistance increment.

2010 ◽  
Vol 154-155 ◽  
pp. 1761-1766 ◽  
Author(s):  
Mohsen Barmouz ◽  
M.K. Besharati Givi ◽  
Jalal Jafari

Friction stir processing (FSP) is a metal-working technique that causes microstructural modification and change in the upper surface of metal components. In this work the effects of tool pin profile on the microstructure and mechanical behavior of reinforced SiC particles metal matrix composites (MMCs) produced by friction stir processing were studied. Optical microscopy (OM) and Scanning electron microscopy (SEM) was employed to carry out the microstructural observations. Vickers Microhardness Machine used for microhardness evaluation. Results show that, tool pin profile play a major role in improvement of the surface quality, SiC particles dispersion in pure copper matrix, hardness behavior and wear resistance. Two different tool pin profile (straight cylindrical and square) were used to perform the process. It was found that, straight cylindrical tool pin profile led to finer grains, uniform dispersion of SiC particles, higher microhardness and wear resistance values.


Author(s):  
Mostafa Akbari ◽  
Parviz Asadi

Multi-walled carbon nanotube/aluminum composites are fabricated on Al–Si cast alloy employing friction stir processing. First, the microstructure of the stir zone, as well as the effect of process parameters on the size of silicon particles, is investigated. Then, the process is numerically simulated using a thermo-mechanically coupled three-dimensional finite element method model. Material flow, as the primary reason for the dispersion of reinforcing particles, is considered in the numerical model, and proper conditions to obtain a uniform dispersion of multi-walled carbon nanotubes are determined. Scanning electron microscope analysis is carried out to consider the particle distribution in the texture of the stir zone. The results show that the particle distribution improves significantly by changing the tool rotation direction between the friction stir processing passes. The hardness test is accomplished on the cross-section of the friction stir processed specimens, and finally, the wear test is performed to compare the wear resistance of the composites with the base alloy. The results show that the wear resistance and hardness of the produced composites are considerably enhanced compared to the base alloy.


Author(s):  
Husain Mehdi ◽  
RS Mishra

In this work, the effect of friction stir processing (FSP) on tungsten inert gas welding (TIG) has been observed to improve mechanical properties and wear resistance behavior of TIG-welded joint of AA7075 and AA6061. The TIG-welded joints were processed by FSP at various tool rotational speeds of 700, 800, 900, 1000, and 1100 r/min with a constant feed rate of 70 mm/min and tilt angle of 1°. The maximum joint efficiency of 92.81% was observed in TIG + FSP-welded joint with filler ER5356 at a rotational tool speed of 1100 r/min. The maximum tensile strength of 284 MPa was observed in TIG + FSP-welded joint with filler ER5356, whereas the minimum tensile strength of 124 MPa was observed in the TIG weldment with filler ER4043. The cleavage facets, tears ridges, and large dimples were observed in fractured specimens of TIG-welded joints, whereas fine and equiaxed dimples were observed in TIG + FSP-welded joints. The maximum micro-hardness of 137 HV in the stir zone was observed in TIG + FSP-welded joint at a rotational tool speed of 1100 r/min. Due to intense precipitate (MgZn2) kept in the stir zone with filler ER5356, the TIG + FSP-welded joints using filler ER5356 have superior wear resistance compared to TIG and TIG + FSP-welded joint with filler ER4043.


2015 ◽  
Vol 787 ◽  
pp. 568-572 ◽  
Author(s):  
A. Radha ◽  
K.R. Vijayakumar

Composite materials like Aluminium metal matrix composite is playing a very important role in manufacturing industries e.g. automobile and aerospace industries, due to their superior properties such as light weight, low density, high specific modulus, high fatigue strength etc., In this study Aluminium(Al 6061) is reinforced with Silicon Carbide particles and fabricated by Stir Casting Technique (vortex method). The MMC rectangular bars (samples) are prepared with Al6061 and SiC (28 µ size) as the reinforced particles by weight fraction from 0%, 5%, 10%, and 15% of SiC. The microstructure analysis and Mechanical properties like Tensile Strength, Vickers Hardness and Charpy Impact Strength were investigated on prepared specimens. It is observed that the properties are increased with increasing of reinforced specimens by weight fraction.


2015 ◽  
Vol 787 ◽  
pp. 421-425
Author(s):  
A. Vignesh ◽  
V.G. Vijay Prakaash ◽  
A.K. Lakshminarayanan

An attempt is made to modify the surface metallurgically and enhance the wear resistance of AISI 316LN austenitic stainless steel using friction stir processing. Friction stir welding tools made up of tungsten based alloy with pin and pinless configuration was used. Fine equiaxed grains were observed in the friction stir processed zone irrespective of tool configuration used. Dry sliding wear resistance was evaluated using pin-on-disc wear tester and it is found that, the friction stir processed zone showed superior wear resistance compared to the base metal. Microstructure, micro hardness, and worn surfaces were used to correlate the results obtained.


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