LM6 Aluminium Alloy Research Articles

Investigation on microstructure and tensile behaviour of stir cast LM13 aluminium alloy reinforced with copper coated short steel fibers using response surface methodology

Copper coated steel fibers reinforced LM13 aluminium alloy composites have been prepared using stir casting process. Experiments have been designed using response surface methodology by varying wt% of reinforcement (0–10), stirrer speed (350–800 rpm) and pouring temperature (700–800 °C). Microstructure, tensile strength and fracture surface of composites have been investigated. Analysis of variance, significance test and confirmation tests have been performed and regressions models have been developed to predict the tensile strength of composites. Response surface plots reveal that tensile strength of composites increases with increasing wt% of copper coated steel fibers reinforcement up to 6 wt%. Further increase in wt% of steel fibers decreases the tensile strength of composites. However tensile strength of composites increases with increasing stirrer speed due to the uniform and homogeneous dispersion of steel fibers in matrix. Optimum stir cast process parameters for obtaining higher tensile strength are found to be 5.9 wt% of reinforcement, 753 °C pouring temperature and stirrer speed of 633 rpm. Fracture mechanism is dominated by steel fiber pullouts in composites with higher wt% of reinforcement and dimples are observed in the surface of composites containing lower levels of wt% of reinforcement.

Effect of stir cast process parameters on wear behaviour of copper coated short steel fibers reinforced LM13 aluminium alloy composites

Copper coated steel fibers reinforced LM13 aluminium alloy composites have been prepared using stir casting process. Experiments have been designed using response surface methodology (RSM) by varying wt% of reinforcement (0–10), pouring temperature (700–800 °C) and stirrer speed (350–800 rpm). Microstructures and dry sliding behaviour of composites have been investigated and reported. Composites prepared using high stirring speed shows uniform dispersion of reinforcement throughout the matrix. Regression equation is developed to predict the weight loss of composites and the error percentage is ±7. Response surface plots reveal that weight loss of composites decreased with increasing wt% of reinforcement and stirrer speed. Stir cast process parameters have been optimised for obtaining minimum weight loss and it’s found to be a wt% of reinforcement of 8.17, pouring temperature of 778 °C and stirrer speed of 658 rpm. Worn surface shows fine grooves and shallow grooves in composites with higher wt% of reinforcement and delamination is observed for the composite contains lower wt% of reinforcement.

Friction, Wear and Mechanical Properties of Al-Si LM6 Cast Alloy Processed in Semi-solid Stage

Dry sliding wear characteristics, mechanical properties and microstructural behavior of powder-chip based reinforcement silicon rich LM6 aluminum alloy, fabricated by semi-solid casting were investigated. Wear tests were conducted on powder-chip reinforced cast samples using the pin on disc apparatus under 5, 10 and 15 N with 0.4, 0.8 and 1.2 m/s sliding speeds for 250, 500 and 750 m sliding distances versus EN31 tool steel hardened to 62 HRC. An observation from the microstructure images indicated that the porosity of the cast composite reduces due to the distribution of un-melted chips inside the short cavities by the addition of reinforcement and confirmed with the obtained results of density. The fracture in cast specimens indicates that the micro-cracks were prevalently propagated along the broken eutectic silicon particles. Additionally, wear resistance was increased reasonably due to the inclusion of reinforcement under metallic wear environment. Worn surfaces SEM, EDS, XRD and, AFM analysis suggests that surfaces plastically deformed along with silicon brittle asperities which stuck on the softer surface of the contact layers, while dominant wear mechanisms were found from these surfaces and wear debris.

Določevanje mehanskih lastnosti livarskih Al-zlitin LM6, ojačanih s pocinkano jekleno mrežo

Določevanje mehanskih lastnosti livarskih Al-zlitin LM6, ojačanih s pocinkano jekleno mrežo

Fabrication of light-weight Al LM13/TiS2 metal matrix composites and investigation of its wear characteristics

ABSTRACTThis paper aims to study the dry sliding wear characteristics of LM13 aluminum alloy matrix containing titanium disulfide (TiS2) as the reinforcement (10 wt%, average size 37 µm) fabricated through liquid metallurgy route. Microstructural examination and Vickers hardness test were performed on the sample to investigate uniform distribution of the reinforcement particles in the composite. Energy Dispersive X-Ray Analysis and X-Ray Diffraction techniques were used to characterize the composite. The hardness test gave a result of 105.94 HV. The dry sliding wear experiments were designed by a five-level central composite design developed using response surface methodology. The factors considered were load, sliding distance, and velocity which were varied in the range of 10–30 N, 500–1500 m, and 1–3 m/s, respectively. The experiments were then performed at room temperature using a pin-on-disc tribometer for 20 combinations. The generated regression equation showed that the developed model established a proper relation between the process variables and the response. Load being the most influential factor showed increasing trends of wear rate in the surface plots against both velocity and sliding distance. The wear rate exhibited a nonlinear trend in the surface plots against sliding distance and velocity. Scanning electron microscopy results showed greater wear at higher loads due to higher surface damage. Thus, the fabricated Al/TiS2 composite with the optimum wear process parameters can be well utilized for application where wear becomes a major consideration.

Investigation on Mechanical Properties and Wear Behaviour of Squeeze Cast LM13 Aluminium Alloy Reinforced with Copper Coated Steel Wires

Abstract Copper coated steel wires (1–5 numbers) reinforced in LM13 aluminium alloy composites have been prepared using squeeze casting process. Microstructure of composites has been investigated and mechanical properties viz., hardness, tensile strength and ductility have been examined and reported. Dry sliding wear behaviour of composites has been investigated by varying sliding distance and load. Fracture surface of broken tensile specimens and worn surface of wear samples have been investigated using field emission scanning electron microscope (FESEM). The results reveal that copper coated steel wires reinforcement in LM13 aluminium alloy improves the mechanical properties and wear resistance. Average hardness values of 136 BHN and 96 BHN have been observed in steel wire and at the interface of steel wire and aluminium alloy, respectively. Tensile strength of composites increased up to 28% by reinforcing three copper coated steel wires in LM13 aluminium alloy. Dry sliding wear test results reveal that weight loss, wear rate and coefficient of friction decreased with increasing number of copper coated steel wires reinforcement in LM13 matrix. However, weight loss of samples increased with increasing sliding distance and load. LM13 aluminium alloy reinforced with five numbers of copper coated steel wires decreased the weight loss up to 69% as compared to LM13 aluminium alloy tested at 40 N load and a sliding distance of 2500 m. Fracture surface of composites shows broken steel wires and dimples are observed in LM13 matrix. Worn surface of composites shows fine and shallow grooves; whereas delamination is observed in LM13 aluminium alloy. In general, copper coated steel wire reinforcement in LM13 aluminium alloy exhibited better mechanical properties and wear resistance compared to matrix.

Effect of mould vibration on the mechanical properties of aluminium alloy castings

This paper presents the effects of mould vibration on the mechanical properties and microstructure of LM6 and LM26 aluminum alloy castings at different vibration frequencies. The vibration frequencies used during the solidification process were 0, 5 and 9 Hz. The mechanical tests conducted were hardness test, tensile test and fatigue test while microstructure analysis was performed using scanning electron microscope. The experimental results show that the mechanical properties of LM6 and LM26 alloys can be improved by vibration. It was observed that increase in vibration frequency up to 9 Hz led to an increase in ultimate tensile strength from 89.11 to 100.17 MPa for LM6 and from 102.42 to 117.65 MPa for LM26 aluminum alloys. It was also found that hardness and fatigue life improved significantly with the increase in vibration frequency. The microstructural studies reveal finer grains, fragmented microstructure, better distribution and low porosity with the increased application of vibration. This leads to less defects and improved mechanical properties in castings products.

Effect of grit size on the wear behavior of LM6/cenosphere composites

The abrasive wear properties of stir-cast LM6 aluminum alloy-10 wt. % cenosphere composite were tested against hard SiC abrasive paper with different grit sizes and compared with the LM6 aluminum alloy. The results show that the abrasive wear resistance of LM6/cenosphere composite is better than the LM6 aluminum alloy for low loads up to 15 N (transition load) on a pin sample. The SWR and coefficient of friction decreases with increasing load. SEM studies reveal the presence of both abrasive and adhesive wear mechanisms and from both the mechanism the abrasive wear mechanism is more prominent and dominating.

Investigation of Mechanical Properties and Dry Sliding Wear Behaviour of Squeeze Cast LM6 Aluminium Alloy Reinforced with Copper Coated Short Steel Fibers

LM6 aluminium alloy with 2.5–10 wt% of copper coated short steel fiber reinforced composites were prepared using squeeze casting process. Microstructure and mechanical properties viz., hardness, tensile strength and ductility were investigated. Dry sliding wear behaviour was tested by considering sliding distance and load. Fracture surface and worn surface were examined using field emission scanning electron microscope (FESEM). Hardness of composites increased with increasing wt% of fiber. Tensile strength of composites increased up to 19% for 5 wt% fiber composites. Further addition of fibers decreased the tensile strength of composites. Ductility of the composites decreased with the addition of fibers into the matrix. Wt% of fibers significantly decreased the weight loss, coefficient of friction and wear rate. Also the cumulative weight loss decreased up to 57% for 10 wt% of composites compared to LM6 aluminium alloy. Fracture surface of composite tensile specimen showed dimple formation and fiber pullout. Worn surface of matrix showed long continuous grooves due to local delamination on the surface. However, worn surface of composites showed fine and smooth grooves due to ploughing rather than local delamination. Copper coated steel fiber reinforcement in LM6 aluminium alloy exhibited better mechanical properties and wear resistance compared to matrix.

Influence of Powder-Chip Based Reinforcement on Tensile Properties and Fracture Behaviors of LM6 Aluminum Alloy

Tensile properties and fracture behaviors of silicon rich LM6 aluminum alloy were investigated in details for as cast alloy and modified by LM6 powdery-chip capsules. The obtained results showed that 20% modified LM6 cast composite ensured the excellent tensile properties (tensile strength of 203 MPa with 3.8% elongation). An impressive increase in the elongation (6.8%) was found for 25% modified cast composite with good ultimate tensile strength, 6.2% higher than unmodified (182 MPa). Characterization of the casts and fracture surfaces were carried out to study the effect of reinforcement particles. An influence of un-melted chip structure was observed inside the cavities and on fractured surfaces. The XRD results showed that cast consisted of inter-metallics of AlO2, Al2Si and Al4Si. It was attributed to micro-cracks prevalently propagated along the broken eutectic silicon particles and some rejected solid particles on the fractured surfaces with ductile and inter-granular fracture. Debonding and cracking of silicon particles were also detected on the fractured surface of the specimens.

Effect of Copper Coating and Reinforcement Orientation on Mechanical Properties of LM6 Aluminium Alloy Composites Reinforced with Steel Mesh by Squeeze Casting

Uncoated and copper coated steel wire mesh reinforcing LM6 aluminium alloy composites have been produced using squeeze casting process by varying reinforcement orientation viz., 0°, 45° and 90° respectively. Microstructure of the castings has been examined and mechanical properties such as hardness, tensile strength and ductility have been investigated. Fracture surface of tensile specimens has been analysed using field emission scanning electron microscope. Microstructure of samples reveals that copper coating on steel wires improves the interface bonding between matrix and reinforcement. Average hardness values of 259 and 90 Hv have been observed in steel wire and matrix respectively. Tensile strength of composites increases with increasing angle of reinforcement orientation from 0° to 90°. Tensile strength increases up to 11% by reinforcing copper coated steel wire mesh at 90° orientation as compared to LM6 aluminium alloy. Fracture surface of composites shows pullout of steel wires in uncoated steel wire mesh composites and broken wires in copper coated steel wire mesh composites respectively. Dimples have been observed on the fracture surface of LM6 aluminium alloy. In general, copper coated steel wire mesh composites offer better hardness and tensile strength compared to uncoated steel wire mesh composites and LM6 aluminium alloy. This may be attributed to the copper coating on steel wires which results better interface bonding between matrix and reinforcement.

Dry sliding wear characterization of squeeze cast LM13/FeCu composite using response surface methodology

Dry sliding wear is one of the predominant factors to be considered while selecting material for automotive and aerospace applications. Researchers have been exploring novel aluminium matrix composites (AMC), which offer minimum wear rate for various tribological applications. In this present work, an attempt has been made to reinforce LM13 aluminium alloy with copper coated steel fibers (10wt.%) using squeeze casting process and to perform dry sliding wear test using pin-on-disc tribometer. Microstructure of cast samples was examined using image analysis system to investigate the dispersion of reinforcement in matrix. Dry sliding wear test was performed by considering factors such as load (10-50 N), sliding velocity (1-5 m∙s-1) and sliding distance (500-2,500 m). Wear test was performed according to the experimental design at room temperature. Three factors and five levels central composite design were used to design the experiments using response surface methodology. Based on the results of the experiments, a regression model was developed to predict the wear rate of composites and checked for its adequacy using significance tests, analyses of variance and confirmation tests. Worn surface of samples was investigated using field emission scanning electron microscope and reported with its mechanisms. Microstructure of cast samples revealed uniform dispersion of reinforcement throughout the matrix. Response surface plots revealed that wear rate of composites increases with increasing load up to 50 N with the velocity 1-5 m∙s-1 and a sliding distance up to 2,500 m. However wear rate decreasesd with increasing velocity at lower loads (up to 20 N) and increased after reaching transition velocity of 2 m∙s-1. Dry sliding wear process parameters were optimised for obtaining minimum wear rate and they were found to be a load of 18.46 N, velocity of 4.11 m∙s-1, sliding distance of 923 m. Worn surface of samples revealed a mild wear at lower loads (up to 30 N), and severe wear was observed at high loads (40-50 N) due to higher level of deformation on the surface.

Effect of pin profile volume ratio on microstructure and tensile properties of friction stir processed aluminum based metal matrix composites

Metal Matrix Composites (MMCs) fabricated via stir casting route are found to have inherent defects such as porosity which deteriorates the mechanical properties. In this investigation, friction stir processing (FSP), an adaptation of friction stir welding (FSW) was used to reduce the level of Porosity of LM25 aluminium alloy matrix with 5% SiC particulates fabricated via stir casting. The pin profile volume ratio (dynamic volume of pin/static volume of pin) plays a vital role in FSP since the actual stirring action and material consolidation are influenced by this parameter. Hence, in this work an attempt has been made to study the effect of pin volume ratio of four different tool pin profiles, namely, straight cylindrical (STC), tapered cylindrical (TAC), threaded cylindrical (THC) tapered threaded cylindrical (TTC). Tensile specimens were extracted from the FSPed area and the tensile properties were evaluated. The micro hardness of the FSPed region was also measured using Vickers hardness tester. From the results it is found that the FSP region produced by tapered cylindrical pin profile exhibited superior tensile properties and hardness compared to its counterparts.

Experimental Evaluation of the Chill Casting Method for the Fabrication of LM-25 Aluminum Alloy-Borosilicate Glass (p) Composites

The paper investigates the novelty of application of end chills in fabricating Aluminum alloy metal matrix composites. An effort has also been made to evaluate the effect of chill material on the soundness of the castings obtained. The required composites were prepared using LM-25 Aluminum alloy as matrix material in which different weight percent of Borosilicate glass particles were added ranging from 3 wt.% to 12 wt.%. The variation in weight percent was brought about in steps of 3%. The fabrication of the composites was carried out in sand molds by incorporating two metallic (copper and Steel) and two non-metallic (Graphite and Silicon carbide) end chills. The specimens for strength and hardness tests were prepared as per ASTM standards and the specimens were drawn from near chill-end as well as from farther away from chill end. The microstructure of the specimens reveal a refined grain structure proving the sound quality of the castings. The result analysis also leads to the conclusion that metallic chills are more beneficial as compared to non-metallic chills for obtaining a good quality composites. Copper chill with a high volumetric heat capacity proved to be the best chill material amongst the others.

Comparative Investigation on Modal analysis of LM25 Aluminium alloy with other Aluminim alloys using Finite element analysis software

The rudimentary steps of the modal analysis and simulation are carried out. The modal analysis is carried out on the different Aluminum Alloys cantilever beam. The cantilever beam is designed in the graphical environment of the ANSYS. The cantilever beam was fine-tuned on one end with all degree of liberation on this end were taken, beam cannot move and rotate. Mode shapes and natural frequencies are premeditated in platforms ANSYS with arithmetical formulation of the direct solver including the block Lanczos method. Aluminum alloys are widely utilized in much application due to their estimable weight to vigor property. Many examination works have been distributed out to make developments the mechanical properties of aluminum alloys. The composition of alloying elements plays a consequential role in deciding the properties of an alloy. In this study a numerical analysis implement i.e., finite element analysis (FEA) is utilized. The work obtainable in this paper is aimed at the study of effect of modal analysis of different aluminum alloys. The modeling and analysis is carried out utilizing ANSYS FEA software. A modal analysis is carried out to understand the modes of frequency demeanor of the material considered. The modal analysis play a vital role in the design of components subjected to high vibration.

Optimization of the Machining parameter of LM6 Alminium alloy in CNC Turning using Taguchi method

Due to widespread use of highly automated machine tools in the industry, manufacturing requires reliable models and methods for the prediction of output performance of machining process. In machining of parts, surface quality is one of the most specified customer requirements. In order for manufactures to maximize their gains from utilizing CNC turning, accurate predictive models for surface roughness must be constructed. The prediction of optimum machining conditions for good surface finish plays an important role in process planning. This work deals with the study and development of a surface roughness prediction model for machining LM6 aluminum alloy. Two important tools used in parameter design are Taguchi orthogonal arrays and signal to noise ratio (S/N). Speed, feed, depth of cut and coolant are taken as process parameter at three levels. Taguchi’s parameters design is employed here to perform the experiments based on the various level of the chosen parameter. The statistical analysis results in optimum parameter combination of speed, feed, depth of cut and coolant as the best for obtaining good roughness for the cylindrical components. The result obtained through Taguchi is confirmed with real time experimental work.

Influence of heat Treatment and aging process on LM13 Aluminium Alloy Cast Sections: An Experimental Study

LM13 Aluminium alloy of variable section sizes have been extensively used in the automotive and aerospace industry. This paper reports the influence of heat Treatment and aging process on the microstructure, mechanical properties of LM13 aluminium alloy sections. Experiment is performed by melting of Aluminium ingot using heat treatment furnace and poured into sand mould cavity of varying section sizes. Microstructure, mechanical properties like hardness, tensile strength and impact strength were measured during as-cast, heat treated and aged condition. ASTM standard B917-01 was followed for heat treatment of LM13 Aluminium Alloy. Cast section was kept at 537°C for 12 hrs for heat treatment, followed by aging at a temperature of 155°C for 5 hrs. The result obtained indicates that at as-cast condition, microstructure changes from coarse to fine with decrease in section size. It was also observed that, mechanical properties also improve with decrease in section size. At heat treated and aged condition, it was observed that almost similar microstructure was observed. Further, the mechanical properties were improved when compared to as-cast condition and variation is irrespective to section size.

Effects of Iron, Manganese, and Cooling Rate on Microstructure and Dry Sliding Wear Behavior of LM13 Aluminum Alloy

ABSTRACTThe presence of Fe in eutectic Al-Si alloy can give rise to formation of a β-Al5FeSi needle-like phase because of low solubility of Fe in this alloy. The brittle nature of this phase leads to decreased mechanical properties of piston alloys, one of which is wear resistance. In this research, to modify β-Fe morphology, Sr and Mn elements were added to the samples prepared from LM13 containing different amounts of Fe. The effect of cooling rate on wear properties of this alloy was also investigated. Results show that the addition of Mn/Fe at aratio of 1/2 can modify the needle-like intermetallics present in the samples containing up to 1.2 wt% Fe. In addition, increasing the cooling rate from 3 to 15°C s−1 refined the eutectic structure and the intermetallics. Hence, it can be considered as another important factor to improve the wear properties of LM13 alloy. To study the wear behavior of this alloy, worn surface and subsurface areas were examined using scanning electron microscopy (SEM) equipped with an energy-dispersive spectrometry (EDS) analyzer.

Characterisation of Silicon Carbide and Fly Ash in LM13 Aluminium Alloy Matrix Composites

The modern vehicles demand more thermal and mechanical properties as the speed of the vehicles is increasing. The materials used should be able to not only withstand the high temperatures but to dissipate it at a faster rate without deformation. This paper investigates the characteristics of silicon carbide (SiC) and fly ash in LM13 aluminium alloy matrix composite prepared by stir casting. The LM13 alloy has high thermal property which makes it ideal for making engines and gears. The effect of fly ash and SiC on LM13 and its influence on increasing the surface roughness was analyzed by varying their proportion. The addition of SiC and fly ash to the matrix composite increases the hardness and tensile strength of the composite which is validated by experimental results.

Experimental analysis to improve energy absorption properties of rectangular metal section subjected to axial loading

This paper aimed to study the aluminiumalloy foam core with mild steel tubes. The aluminium foam was made with LM25 aluminium alloy 15wt% silicon carbideparticle. Aluminium foam core thickness of (18×18) mm was used for making mild steel foam filled tube. The mild steel foam filled tubes were tested in Universal Testing Machine. The energy absorption rate per unit volume was noted that 11.78 to 15.00 MJ/m3 and 12.49 to 17.33 MJ/m3 empty and foam filledmildsteeltubei.e.rectangularshape respectively. This work also describes the compression movementsof mild steel tube and foamfilled tube with foam, variable strain rate between 10-3/s to 10/s at room temperature. The compressive deformation behaviour of thisLM25 aluminium alloy foam filled mild steeltubeand empty mild steel tube was examined in order to evaluate its specific energy absorption. It is also noted that foam filled mild steel tubes stress strain diagram exhibited more energy absorption properties.