Optimization of dry sliding wear parameters of recursive friction stir processed aluminium 7075 alloy

Author(s):  
G Girish ◽  
V Anandakrishnan

In this work, the dry sliding wear behaviour of recursively friction stir processed AA7075 was investigated using a pin-on-disc wear testing apparatus. The microstructure of the processed specimen was probed using optical microscopy, transmission electron microscopy and atomic force microscopy. Experiments were conducted using Taguchi experimental design by varying three different parameters like load, sliding velocity and sliding distance, and the analysis of variance was performed to identify the influence of the parameters over the wear rate. From the main effect plot, the combination of 9.81 N of load, 2 m/s of sliding velocity and a sliding distance of 2000 m was identified as the optimum levels that minimize the wear rate. The regression model was developed to calculate the wear rate, and the validation test was performed with the optimum parameter combination and compared with the experimental results. Wear tracks were examined using field-emission scanning electron microscopy to identify the type of wear mechanism.

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Naveed Anjum ◽  
S. L. Ajit Prasad ◽  
B. Suresha

The mechanical properties and dry sliding wear behaviour of glass fabric reinforced epoxy (G-E) composite with varying weight percentage of silicon dioxide (SiO2) filler have been studied in the present work. The influence of sliding distance, velocity, and applied normal load on dry sliding wear behaviour has been considered using Taguchi's L9orthogonal array. Addition of SiO2increased the density, hardness, flexural, and impact strengths of G-E composite. Results of dry sliding wear tests showed increasing wear volume with increase in sliding distance, load, and sliding velocity for G-E and SiO2filled G-E composites. Taguchi's results indicate that the sliding distance played a significant role followed by applied load, sliding velocity, and SiO2loading. Scanning electron micrographs of the worn surfaces of composite samples at different test parameters show smooth surface, microploughing, and fine grooves under low load and velocity. However, severe damage of matrix with debonding and fiber breakage was seen at high load and velocity especially in unfilled G-E composite.


2017 ◽  
Vol 52 (17) ◽  
pp. 2281-2288 ◽  
Author(s):  
S Sivakumar ◽  
S Senthil Kumaran ◽  
M Uthayakumar ◽  
A Daniel Das

The dry sliding wear behaviour of LM 24 aluminum alloy composites reinforced with garnet particles was evaluated. Stir casting technique was used to fabricate the composites. A pin-on-disc wear-testing machine was used to evaluate the wear rate, in which an EN 24 steel disc was used as the counterface. Results indicated that the wear rates of the composites were lower than that of the matrix alloy and further decreased with the increase in garnet content. However, in both unreinforced and reinforced composites, the wear rate increased with the increase in load and the sliding speed. Increase in the applied load increased the wear severity by changing the wear mechanism from abrasion to particle cracking-induced delamination wear. It was found that with the increase in garnet content, the wear resistance increased monotonically. The observations have been explained using scanning electron microscopy analysis of the worn surfaces and the subsurface of the composites. In this work, the most influencing input and output parameters have been performed and the process parameters have been prioritized using genetic algorithm. Genetic algorithm is used to optimize the most influencing input as well as output process parameters. The practical significance of applying genetic algorithm to dry sliding wear behavior process has been validated by means of computing the deviation between predicted and experimentally obtained wear behavior of metal matrix composite.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Vineet Tirth

AA2218–Al2O3(TiO2) composites are synthesized by stirring 2, 5, and 7 wt % of 1:2 mixture of Al2O3:TiO2 powders in molten AA2218 alloy. T61 heat-treated composites characterized for microstructure and hardness. Dry sliding wear tests conducted on pin-on-disk setup at available loads 4.91–13.24 N, sliding speed of 1.26 m/s up to sliding distance of 3770 m. Stir cast AA2218 alloy (unreinforced, 0 wt % composite) wears quickly by adhesion, following Archard's law. Aged alloy exhibits lesser wear rate than unaged (solutionized). Mathematical relationship between wear rate and load proposed for solutionized and peak aged alloy. Volume loss in wear increases linearly with sliding distance but drops with the increase in particle wt % at a given load, attributed to the increase in hardness due to matrix reinforcement. Minimum wear rate is recorded in 5 wt % composite due to increased particles retention, lesser porosity, and uniform particle distribution. In composites, wear phenomenon is complex, combination of adhesive and abrasive wear which includes the effect of shear rate, due to sliding action in composite, and abrasive effect (three body wear) of particles. General mathematical relationship for wear rate of T61 aged composite as a function of particle wt % load is suggested. Fe content on worn surface increases with the increase in particle content and counterface temperature increases with the increase in load. Coefficient of friction decreases with particle addition but increases in 7 wt % composite due to change in microstructure.


2021 ◽  
pp. 1-18
Author(s):  
Kartheesan S ◽  
B. Shahul hamid Khan ◽  
M Kamaraj ◽  
Manoj Gupta ◽  
Sravya Tekumalla

Abstract In this study, a pure magnesium material reinforced with 0.5, 1, 1.5, and 2 weight % of CaO was prepared through disintegrated melt deposition technique. Nanocomposites were investigated for their sliding wear behaviour in dry condition at room temperature. Amount of CaO, Load, sliding distance, and Sliding velocity were selected as input design parameters at their five-level in central composite design using Minitab 18.1 statistical software. The influence of design parameters on wear loss is reported through the Response Surface Methodology (RSM). ANOVA was used to confirm the soundness of the developed regression equation. The results indicate the contribution of linear, quadratic, and interaction terms of design parameters on response. 3D response surface and 2D contour plots are indicated the interaction effect. The result shows that an increase in sliding velocity contributes to a decrease in the wear loss of the composites because of the emergence of protective oxidative layer at the surfaces of the pins, which is confirmed through FESEM and EDAX analysis of the pin surfaces. Wear loss of the material decreased as amount of CaO increased. The ANOVA analysis concluded that the sliding distance and load contribute significantly to wear loss of the composites and their percentage of contribution is 64.02 % and 3.69%.


2014 ◽  
Vol 10 (2) ◽  
pp. 276-287
Author(s):  
Rajesh Siriyala ◽  
A. Gopala Krishna ◽  
P. Rama Murthy Raju ◽  
M. Duraiselvam

Purpose – Since, wear is the one of the most commonly encountered industrial problems leading to frequent replacement of components there is a need to develop metal matrix composites (MMCs) for achieving better wear properties. The purpose of this paper is to fabricate aluminum MMCs to improve the dry sliding wear characteristics. An effective multi-response optimization approach called the principal component analysis (PCA) was used to identify the sets of optimal parameters in dry sliding wear process. Design/methodology/approach – The present work investigates the dry sliding wear behavior of graphite reinforced aluminum composites produced by the molten metal mixing method by means of a pin-on-disc type wear set up. Dry sliding wear tests were carried on graphite reinforced MMCs and its matrix alloy sliding against a steel counter face. Different contact stress, reinforcement percentage, sliding distance and sliding velocity were selected as the control variables and the response selected was wear volume loss (WVL) and coefficient of friction (COF) to evaluate the dry sliding performance. An L25 orthogonal array was employed for the experimental design. Optimization of dry sliding performance of the graphite reinforced MMCs was performed using PCA. Findings – Based on the PCA, the optimum level parameters for overall principal component (PC) of WVL and COF have been identified. Moreover, analysis of variance was performed to know the impact of individual factors on overall PC of WVL and COF. The results indicated that the reinforcement percentage was found to be most effective factor among the other control parameters on dry sliding wear followed by sliding distance, sliding velocity and contact stress. Finally the wear surface morphology of the composites has been investigated using scanning electron microscopy. Practical implications – Various manufacturing techniques are available for processing of MMCs. Each technique has its own advantages and disadvantages. In particular, some techniques are significantly expensive compared to others. Generally the manufacturer prefers the low cost technique. Therefore stir casting technique which was used in this paper for manufacturing of Aluminum MMCs is the best alternative for processing of MMCs in the present commercial sectors. Since the most important criteria of a dry sliding wear behavior is to provide lower WVL and COF, this study has intended to prove the application of PCA technique for solving multi objective optimization problem in wear applications like piston rings, piston rods, cylinder heads and brake rotors, etc. Originality/value – Application of multi-response optimization technique for evaluation of tribological characteristics for Aluminum MMCs made up of graphite particulates is a first-of-its-kind approach in literature. Hence PCA method can be successfully used for multi-response optimization of dry sliding wear process.


2009 ◽  
Vol 423 ◽  
pp. 125-130 ◽  
Author(s):  
Alvaro Mestra ◽  
Gemma Fargas ◽  
Marc Anglada ◽  
Antonio Mateo

Duplex stainless steels contain similar amounts of austenite  and ferrite α. This two-phase microstructure leads to an excellent combination of mechanical properties and corrosion resistance. However, there are few works dealing with the wear behaviour of these steels. This paper aims to determine the sliding wear mechanisms of a duplex stainless steel type 2205. In order to do it, three different sliding velocities (0.2, 0.7 and 1.2 m/s) and six sliding distances (500, 1000, 2000, 3000, 4000 and 5000 m) were selected. The results show that wear rate depends on both sliding velocity and sliding distance. The wear mechanisms detected were plowing, microcracking and microcutting (typical mechanisms of fatigue wear). These mechanisms evolve according to sliding velocity and sliding distance, highlighting a transition zone in which wear rate is reduced.


2015 ◽  
Vol 766-767 ◽  
pp. 219-228 ◽  
Author(s):  
N.G. Siddeshkumar ◽  
G.S. Shiva Shankar ◽  
S. Basavarajappa

An attempt has been made to study the dry sliding wear behaviour of Aluminium based hybrid composites in room temperature.Al 2219 is used as base material with B4C and MoS2 as reinforcements. The hybrid composite were prepared by conventional stir casting technique. The dry sliding wear test were carried out for various parameters like sliding distance, applied load and sliding speed. The Optical Microscope and SEM results showed the presence of B4C and MoS2, which are fairly uniform and randomly dispersed on matrix material.XRD analysis, shown the presence of B4C and MoS2 phases in the prepared composites.The incorporation of reinforcement particles B4C and MoS2 reduces the specific wear rate of composites. The addition of MoS2 as a secondary reinforcement has significant effect on reducing specific wear rate of prepared composites. By using SEM worn surface of hybrid composites were studied.


2021 ◽  
Vol 9 ◽  
Author(s):  
R. Kousik Kumaar ◽  
◽  
K. Somasundara Vinoth ◽  
Kavitha M ◽  
◽  
...  

This article aims in exploring the dry sliding wear performances on the aluminum (AA7075) metal matrix composites reinforced with molybdenum disulphide which is a solid lubricant using response surface methodology (RSM). Specific Wear Rate (SWR) for the AA7075 pure alloy, AA7075+2wt% molybdenum disulphide and AA7075+4wt% molybdenum disulphide were measured according to ASTM G99 standards in pin-on-disc apparatus. Design of experiments was selected with changed parameters like the varying percentage of molybdenum disulphide (%), applied load (N), and sliding velocity (m/s) based on Central Composite Design in response surface methodology considering them as continuous factors. Experiments for the specific wear rate of pure alloy and the composites were conducted. The volume loss was measured using the pin-on-disc apparatus from which the specific wear rate value was calculated. The obtained results are analyzed and a mathematical model was formulated using the response surface methodology. The optimum level parameters for the specific wear rate has been identified and the results of the experiment specify that the sliding velocity and molybdenum disulphide percentage have a substantial role in controlling the wear behaviour of composites when compared with the other parameter. The optimum condition for the specific wear rate was identified and experimented with for studying the result.


2013 ◽  
Vol 6 (2) ◽  
pp. 139-153
Author(s):  
Israa .A.K

This research is devoted to study the effect of addition of different weight percent from SiCp ( 2, 4, 6, 8 ) to Al– 4 Cu alloy which have been fabricated by liquid metallurgy method on the dry sliding wear behavior and mechanical properties. Wear characteristics of Al–SiC composites have been investigated under dry sliding conditions and compared with base alloy. Dry sliding wear tests have been carried out using pin-on-disk wear test under normal applied loads 5, 10, 15 and 20 N and at different sliding velocity of (2.7, 3.7, 4.7) m/sec. It was also observed that the wear rate varies linearly with increases normal applied load but lower in composites as compared to the base material. The wear mechanism appears to be oxidative for both Al – Cu alloy and composites under the given conditions of load and sliding velocity as indicated by optical microscopic of the worn surfaces. Further, it was found from the experimentation that the wear rate decreases linearly with increasing weight percent of silicon carbide. The best results have been obtained at 8 % wt SiC . We also observed that the yield strength, tensile strength increases with increasing wt% of SiC , but the ductility decreases.


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