Stir Casting Route Research Articles

In-situ synthesized polymer-derived SiC reinforced aluminum matrix composites

In the current work, in-situ formed polymer-derived SiC reinforced aluminum-based metal matrix composites were synthesized to uniformly distribute ceramic particles in metal matrix with good matrix-reinforcement interface. Polymeric precursor (allyl hydrido polycarbosilane) was cross-linked at 300 °C and the cross-linked precursor was mixed with molten aluminum at 800 °C under nitrogen using stir casting route to obtained composites reinforced with 2 wt%, 4 wt% and 7 wt% of SiC (particle size < 10 µm) distributed uniformly in the synthesized composites. Structural characterization of samples were performed using FTIR, XRD, optical microscopy, FESEM and Raman spectroscopy. The composites demonstrated significant improvements in hardness (∼58%), ultimate tensile strength (∼45%) and compressive strength (∼58%) for 7 wt% in-situ formed SiC in aluminum matrix compared to pure aluminum.

Characterization, Strength and Wear Optimization of Aluminium Based Boron Carbide/Graphite Hybrid Composite by TOPSIS for Dry Condition

Aluminium is one of the most widely available metals and its application is seen vastly due to its high strength-to-weight ratio as compared to other metals being cost effective at the same time. Its application is found to be in various structural, automobile and machine industries. But somehow due to its ductile nature, challenging conditions like high-speed applications with minimal wear and friction loss are an important aspect to look forward to. Al6063-based hybrid composites having boron carbide (B4C) 4% wt. and graphite (Gr) 0/2/3.5/5% wt. composites have been fabricated by the stir casting route using K2TiF6 for enhancing the particle dispersion in the metal matrix. XRD, SEM and EDAX results have been obtained for the composites fabricated for characterization. Impact and hardness test results show improvement in the toughness and hardness of the fabricated composites. SEM images of the fractured specimen have been obtained which depict the inhibition of crack propagation due to the boron carbide and graphite reinforcement’s presence. Pin-on-disc wear tests have been carried out considering the L25 Taguchi orthogonal array along with TOPSIS optimization for finding the best and the worst conditions for wear analysis considering the closeness coefficient, C j .

Evaluating mechanical behavior and wear properties of magnesium‐cerium binary alloy produced by stir casting route

AbstractIn the present work, magnesium cerium binary alloy with varying cerium content (0.5 %, 1 %, 1.5 % and 2 %) has been produced by stir casting and microstructure, mechanical properties and wear characteristics have been investigated. From the microstructural observations, development of intermetallic at the grain boundaries was observed with higher cerium content. X‐ray diffraction analysis of the produced samples indicated peaks corresponding to solid solution grains of magnesium and cerium and Mg12C intermetallic. Hardness measurements showed improved values for the alloy with 1.5 % and 2 % cerium. Tensile test results demonstrated higher strength at the cost of losing ductility with the increased cerium content. Enhanced mechanical performance in the alloys with higher cerium can be attributed to the presence of intermetallics at the grain boundaries. Increased wear resistance as reflected from the lower frictional force and wear has been observed for the alloy with 2 % cerium.

Mechanical and tribological characteristics of hypo eutectic Al-7Si alloy-based composite reinforced with Sn metal powder and Al2O3 using bottom pouring stir casting technique

The present work highlights the significant effects of varying wt% of Sn metal powder in the hypo eutectic Al-7Si/10 wt% Al2O3 composite. The composites were manufactured through a multi-stage stir casting route and characterized for mechanical and wear behavior using ASTM standards. The results revealed that the increase in Sn content up to 4 wt% in the matrix enhanced the microhardness, tensile properties, and reduced the porosity. The Al-7Si/10 wt% Al2O3 composite with 4% Sn particle reinforcement shows the highest tensile strength and hardness of 132 MPa and 90 BHN, respectively. All composites exhibited a ductile mode of failure, as evidenced by the tear ridges and dimples on the tensile fracture surface. By adding of Sn metal powder to the material system, the wear rate and coefficient of friction were reduced. At 1000 m of sliding distance and 1 ms−1 of sliding velocity, the wear loss of 8 wt% Sn composite was decreased by 88.8% as compared to Al-7Si base alloy at a normal load of 10 N whereas, at 40 N of normal load, the wear loss was decreased by 66.6%. During the wear process, the Sn metal powder surfaced and formed a thin tribo film that mechanically mixed with the surface, resulting in reduced friction. The layer at the interface prevented direct contact between asperities on the mating surface, which reduced wear loss. The composites without Sn metal powder exhibited adhesive wear and delamination as the primary wear mechanisms, while composites with Sn showed predominantly adhesive wear. Regression analysis followed by a desirability function approach was carried out to develop the model and optimize the operating conditions of the experiments.

Optimizing abrasive wear loss of Aluminum/Fly Ash and Aluminum/Rice Husk Ash metal matrix composites using AHP-EDAS and AHP-COPRAS techniques for enhanced performance

Lightweight aluminum metal matrix composites (MMCs), Aluminum/Fly Ash and Aluminum/Rice Husk Ash were developed using the stir casting route for automotive applications. As a result of the above consideration, automotive parts such as brake rotor and connecting rod, etc. have been the subject of research in a variety of areas. Finding the right material for the design under consideration requires an effective approach to material selection. Multi-criteria decision-making (MCDM) processes are helpful when dealing with ambiguity in material selection. To rank aluminum-Fly Ash (FA) and Aluminum-Rice Husk Ash (RHA) composites, integrated MCDM methodologies such as Analytical Hierarchy Process (AHP)–Evaluation Based on Distance from Average Solution (EDAS) and AHP–Complex Proportional Assessment (COPRAS) are utilized. The weights for each criterion are determined using the AHP approach, and the EDAS and COPRAS techniques are then used to rank the items. Three different particle sizes (0–53, 54–74, and 75–105 µm) of the reinforcement have been chosen for the selection criteria. Density, hardness, ultimate tensile strength, and compressive strength, and specific wear rate, and coefficient of friction of the manufactured composites evaluated. A thorough examination of the MCDM methods found that Al-FA composites with particle sizes of 54–74 µm were the most effective.

Developing a steady state wear equation for AA7050 hybrid composites/steel interface at elevated temperature

ABSTRACT In this research work, an attempt was made to reinforce AA7050/5Gr composites with multi-walled carbon nanotube (MWCNT) of varying weight percentages processed through stir casting route. SEM with EDS mapping revealed that the particles were uniformly distributed over the composites. Hardness reduces with increasing MWCNT weight percentage owing to the inverse hall petch effect and increment in void content. A third-body abrasion, which happens when the CNT in the aluminium matrix material detaches from the surface and erodes material from the composites pin as well as the counter face, causes the wear resistance to rise with the addition of CNT particles. A mechanically mixed layer, which avoids direct metal-to-metal contact and thus increases wear resistance, was created at the abraded surface and at high temperature, where the reduction of wear rate was due to the development of oxide protective layer. A steady-state wear equation for the contacting surface at high temperature (R = 1/Y √(ln W/2X)) for AA7050 hybrid composites–steel interface was developed. The enhancement in wear resistance was directly proportional to the proportion of ferrous content present on the surface, which was confirmed on the elemental analysis. Pock marks, micropits, craters and cracks were the features observed on the worn surface morphology, whereas delamination and plasticisation were the observed modes of wear mechanism.

Electrochemical corrosion behaviour of rolled dual phase Mg-8Li-graphene composite

In this research, the effect of interrupted rolling on electrochemical corrosion behaviour of Mg-8Li-xGr composite is investigated. Graphene reinforced composite was developed by using stir casting route and rolled with different reductions in thickness of 50, 75 and 90%. Investigation on potentiodynamic polarization of rolled composite depicts that increase in reduction percentage increases the corrosion rate of the developed composite. Electrochemical impedance studies reveal that composite reduced at 50% thickness exhibits higher charge transfer resistance of 80 Ωcm2. Nyquist plot depicts occurrence of inductance loop that reveals occurrence of oxide layer breakage. Addition of graphene up to 0.4 wt% increase the corrosion resistance and further addition exhibits adverse effect in corrosion behaviour due to the galvanic effects. The occurrence of pitting corrosion is evidenced from corrosion surface morphology.

Experimental And Finite Element Analysis of Tensile Behavior of Stir Casted Magnesium Alloy Az91

In this present project work the significance of light weight material is discussed. The conventional light weight metal aluminum is replaced by magnesium. In addition magnesium based alloys are superior properties and most widely applicable in automobile and aircraft materials. High-quality samples of magnesium alloy AZ91 is fabricated through stir casting route. The use of wire cut EDM for sample preparation proved to be a reliable and accurate method for creating uniform samples with consistent dimensions. The ultimate tensile strength (UTS) of the magnesium alloy AZ91 obtained through the wire cut EDM tensile test was 174 MPa, indicating that the material is strong and able to withstand high levels of tensile stress. The ANSYS simulation predicted a slightly lower UTS value of 169 MPa, indicating that the simulation method may have made certain assumptions about the material's behavior that did not match the experimental results. The difference of 5 MPa between the experimental and simulated UTS values suggests that there may be some room for improvement in the simulation methods used in ANSYS software. The results of this study provide valuable information for engineers and materials scientists working with magnesium alloy AZ91, as they demonstrate the material's behavior under tensile loading and highlight potential areas for improvement. Hence the fabricated material is tested experimentally and numerically for its tensile properties. Hence the present work is significant for need of light weight material in automobile and aircraft applications.

Wear characterization of zirconium diboride (ZrB2) reinforced AA7178 matrix composites produced by stir casting route

Wear characterization of zirconium diboride (ZrB2) reinforced AA7178 matrix composites produced by stir casting route

Investigation of the mechanical, corrosion, and tribological characteristics of AZ61 Mg with boron carbide nano particles via the stir casting route

Abstract Magnesium composites are innovative, compact, and distinctive materials. Because of their low density, magnesium composites are suitable for applications in the automobile, aviation, semiconductor, and pharmaceutical sectors. To enhance the mechanical wear and corrosion behavior of theAZ61 Mg alloy, different weight percentages of nano-B4C reinforcements (2.5, 5, 7.5, and 10wt%) were strengthened with magnesium matrix. Fabrication of magnesium composites was achieved through the stir casting method. The as-cast specimens were subjected to microstructural analysis, which showed that the B4C nanoparticles were dispersed uniformly, well bonded to the matrix, and had a minimal level of porosity. This shows that the inclusion of B4C nanoparticles has aninsignificanteffect on the microstructure of the as-cast material. The material’s tensile strength, compressive strength, hardness, corrosion resistance, and wear resistance were all greatly increased by the Mg17Al12 phase’s fracture and dispersion. Scanning electron microscopy was utilized to inspect the surfaces of AZ61/B4C nanocomposites and witnessed the uniform dispersal of reinforcement within the matrix.The maximum value for mechanical properties was obtained for AZ61/7.5wt%B4C nanocomposite and the lowest value was found to be the corrosion test. These results show that the AZ61/7.5wt%B4C nanocomposite is a superior material for aerospace and automotive engineering components where high compressive strength, corrosion resistance, and wear resistance are required.

Optimization of spark erosion machining on synthesized boron carbide based bronze composite

The development and research is about advanced composite that is been highly increased in all sectors of all modern industries. The material with reinforcement of carbides has provided the exceptional substance properties. Boron carbide reinforced bronze composite is synthesized using stir casting route. A weight proportion of B4C with 1.5% were considered for the investigation. The present investigation and the objective is to optimize by Taguchi approach on synthesized boron-carbide based bronze composite. The evaluation of substance properties and characterization were investigated. The characterization studies and confirmation of elemental role were investigated by Scanning electron microscope (SEM). The machinability behaviors of synthesized bronze composite are analyzed by EDM process with copper chromium tool. The machined surface was investigated using atomic force microscopy.

MICRO-GROOVING OF ALUMINUM-BASED COMPOSITES USING Nd:YAG LASER MACHINING

This paper describes the pulsed Nd:YAG laser machining characteristics on 6351 aluminum reinforced with silicon carbide (SiC) and boron carbide (B4C) particles. The composites are prepared using stir casting route by varying the weight percentage of B4C (0, 5, and 10 wt.%). During experimentation, the traverse speed (5, 15, and 30 mm/s) and the laser pulse frequency (5, 9, and 15 kHz) are considered to evaluate the groove width. The results reveal that the lower pulse frequency produced poor groove surface quality. Higher thermal energy dissipation at lower traverse speed may also result in the formation of recast layer and heat-affected zone. This is evident from the microscopic image and the EDS analysis. Thus, the optimum condition (composite with 10 wt.% B4C machined at 30 mm/s and 15 kHz) to achieve minimum grove width with improved surface morphology is identified by desirability analysis. Additionally, the regression model is developed to predict future values ([Formula: see text] at 91.86% and [Formula: see text] (adj) at 87.55%). Finally, the probability plot confirms the effectiveness of the proposed model at 95% confidence level.

Taguchi optimizations on friction stir welding of nitinol alloy

The welding strength plays a vital role in all manufacturing sectors in welding proces. At the same time, advanced materials with reinforced particles offers good welding strength. The admirable weldability characteristics are attained by friction stir welding process (FSW). Cubic Boron Nitride - CBN, Titanium Zirconium Molybdenum - TZM acts as a tool material in FSW process which gives good welding strength when compared to other tool material. Silicon carbide based nitinol composite is manufactured by stir casting route which provides admirable substance properties. Scanning Electron Microscope (SEM) was used to analyze the material characteristics. The welding strength obtained from two tool materials were compared. The optimal strength of the joint is attained by Taguchi optimization. The objective of the research work is to increase the welding strength using TZM tool. Optimal strength of welding was obtained at rotational speed of tool: 1499.9 rpm, speed of welding at 49.9 mm/min, feed: 9.9 mm/min.

Optimization of stir casting and drilling process parameters of hybrid composites

AA2219 alloy is widely used in aerospace and automobile applications, wherein the properties can be enhanced with 15% wt. of B4C reinforcement particles. Assembly task in aerospace application requires drilling millions of holes, and it is often challenging to obtain good-quality drilled holes due to the presence of hard B4C particle reinforcements. The self-lubricating capability of molybdenum disulfide (MoS2) and Graphene (Gr) materials was used as secondary reinforcements to improve the drilled hole quality characteristics. The stir-casting route fabricates the hybrid composites (AA2219 alloy/B4C/Gr/MoS2). The hardness and wear resistance properties of hybrid composites are affected by the influencing process variables such as percent reinforcement of Gr and MoS2, stirring speed, and pouring temperature. Taguchi L9 matrix is used for experimentation and performs statistical analysis. All stir-casting variables are found to make significant contributions toward hardness and wear resistance. The limitation of the Taguchi method to solve multiple objective optimizations is solved by applying Data Envelopment Analysis Ranking (DEAR) method. A DEAR method determined optimal conditions (Gr and MoS2: 1.5 wt%, stir speed: 400 rpm, and pouring temperature: 760 °C) resulted in a reduced wear rate of 1.65 × 10−3 mm3/min and 128 HV hardness in hybrid composites. The hybrid composites were prepared for the determined optimal stir casting conditions. Drilling experiments were carried out to analyze the variables such as feed rate (FR), drilling speed (DS), and drill tool material (DM): high-speed steel: HSS, carbide: C, and coated carbide: CC that affect the hybrid composite hole quality characteristics such as burr height: BH, material removal rate: MRR, and thrust force: TF. A DEAR method determined optimal drilling conditions (FR: 0.25 mm/rev; DS: 20 m/min; DM: coated carbide drill tool) resulted in 645 mm3/min of MRR, 2.95 kN for TF, and 0.16 mm for BH, respectively. The self-lubricating capability of Gr and MoS2 reinforcement particles in hybrid composites ensures excellent composite properties and drilled-hole quality characteristics. Taguchi and DEAR methods employ simple mathematical steps which can be used by novice industry personnel to perform optimization for other output characteristics.

In vitro degradation and dry sliding wear behaviour of AZ31-Sn/Al2O3 nano metal matrix composites in simulated body fluid for biomedical application

In this research, tin was added to the AZ31/2Al2O3 magnesium metal matrix composite to investigate its influence on degradation rate in the presence of simulated body fluid (SBF) and wear behaviour in dry conditions. The AZ31- xSn/2Al2O3 ( x = 0, 2, 4, 6, 8, and 10 wt%) composites were manufactured using the bottom pouring stir casting route. The microstructure of the manufactured AZ31/2Al2O3 and AZ31- xSn/2Al2O3 composites revealed that they were composed of the α-Mg solid solution and the intermetallic compound □-Mg17Al12, which was situated near the grain boundaries. When tin was added, the Sn-rich intermetallic compound Mg2Sn was formed, increasing the volume fraction of the Mg2Sn phase. Compared to AZ31/2Al2O3 composite, the wear test revealed that AZ31/2Al2O3 composites containing Sn particles exhibited a higher ability to generate more stable tribo-layers at higher applied loads, which protected the worn surface and reduced the wear rate. The wear resistance of composites was improved primarily by the behaviour of the tribo-layer in the wear process. The degradation rates (mm/year) of the AZ31 composites were carried out for 72 h in SBF. The degradation rate was reduced when the Sn content in the AZ31/2Al2O3 composite was increased to 6 wt% and then increased with further Sn addition. It was observed that when the amount of Sn particles increases up to 6 wt%, the severity of the degradation decreases.

Study on mechanical characteristics of stir cast Al ADC12/B4C metal matrix composite

Automobile parts with ferrous components have been replaced by light metal alloys and their composites to minimize the pollution impact and enhance the safe environment. Al ADC12 alloy with various weight percentages (2%, 4% and 6%) of Boron Carbide (B4C) particles was cast in the stir-casting route. The mechanical characteristics of the composite samples were evaluated with tensile and wear tests. The uniform distribution of B4C with Al ADC12 composite due to the stirring action implies relatively improved results compared with base aluminium alloy. However, the composition of 6% B4C composite produces a considerable result on tensile strength and wear resistance. The stirring action of the casting process enhances the better distribution of reinforcements with matrix elements; it reveals the improvement in tensile properties and wear resistance of the composites.

Influence of TiO2 and Y2O3 nanoparticles on mechanical properties of aluminium matrix hybrid nanocomposites fabricated by vacuum die casting

Purpose The purpose of this paper is to evaluate the effect of titanium oxide (TiO2) and yttrium oxide (Y2O3) nanoparticles-reinforced pure aluminium (Al) on the mechanical properties of hybrid aluminium matrix nanocomposites (HAMNCs). Design/methodology/approach The HAMNCs were fabricated via a vacuum die-assisted stir casting route by a two-step feeding method. The varying weight percentages of TiO2 and Y2O3 nanoparticles were added as 2.5, 5, 7.5 and 10 Wt.%. Findings Scanning electron microscope images showed the homogenous dispersion of nanoparticles in Al matrix. The tensile strength by 28.97%, yield strength by 50.60%, compression strength by 104.6% and micro-hardness by 50.90% were improved in HAMNC1 when compared to the base matrix. The highest values impact strength of 36.3 J was observed for HAMNC1. The elongation % was decreased by increasing the weight percentage of the nanoparticles. HAMNC1 improved the wear resistance by 23.68%, while increasing the coefficient of friction by 14.18%. Field emission scanning electron microscope analysis of the fractured surfaces of tensile samples revealed microcracks and the debonding of nanoparticles. Originality/value The combined effect of TiO2 and Y2O3 nanoparticles with pure Al on mechanical properties has been studied. The composites were fabricated with two-step feeding vacuum-assisted stir casting.

Experimental study and TiC interfacial action on microstructural and mechanical properties of AZ31 alloy composite made by stir casting route

The attention of magnesium alloy nanocomposite prepared with ceramic particle gathering is necessary for structural, marine, automobile, aviation, and defence applications because of its low density, high strength, castability, and ease of recycling. The different weight percentages (0, 2, 4, 6, and 8 wt%) of TiC nanoparticle reinforced magnesium alloy (AZ31) alloy synthesized by stir casting route and find the interface action on microstructural and mechanical characteristics of AZ31 alloy nanocomposites. The scanning electron microscopic images of the composite samples found uniform distributed TiC particles, and more than 6 wt% showed the agglomerated particle. The yield and tensile strength of composite (6 wt% TiC) was increased by 7.64% and 14.6% compared to the cast AZ31 alloy. The maximum hardness (112.5 ± 0.87Hv) was observed by AZ31/8 wt% composite. The tensile fracture of AZ31 alloy nanocomposite with 8 wt% was analyzed, and found poor interfacial action between the AZ31 and TiC. The higher content of TiC leads to brittle nature.

ENHANCEMENT IN MICROSTRUCTURAL CHARACTERISTICS AND MECHANICAL PROPERTIES OF A6082-BASED MMCS VIA YTTRIA STABILIZED ZIRCONIA INCORPORATION AND T6 HEAT TREATMENT

This study investigates the impact of Yttria Stabilized Zirconia (YSZ) and T6 heat treatment on the mechanical and microstructural properties of A6082-based Metal Matrix Composites (MMCs) prepared using the conventional stir casting route. A6082 is widely used in various industrial applications due to its excellent physical, structural and functional properties with good corrosion resistance. YSZ with superior mechanical and thermal properties that can enhance the strength and wear resistance of aluminium-based composites. T6 heat treatment is a widely adopted technique to improve the material properties of aluminium alloys. The results of this study indicate that the T6 heat treatment significantly refines the grain structure of the composites, resulting in improved hardness and tensile values compared to untreated samples. Mechanical properties are also enhanced by YSZ's integration into the composites, with a 9wt.% YSZ addition to the matrix alloy leading to a noticeable improvement in hardness for both the untreated and treated composites. The tensile parameters show a similar trend, with a gain in Ultimate Tensile Strength and Yield Strength up to 6wt.% YSZ addition, after which the findings follow a downtrend (at 9wt.%). The results of this research show that A6082/YSZ composites subjected to T6 heat treatment have great promise as a high-performance material.

Electric Discharge Machining of AA7075/SiCP/B4CP Hybrid Composites machined with Al2O3 Mixed Used Engine Oil Dielectric fluid

Background: Machining hybrid composites through conventional machining technique was a challenging task as it produces excessive tool wear and exhibits poor surface roughness. In this research work, an attempt was made to electric discharge machining of AA7075/SiCP/B4CP Hybrid Composites produced through the stir casting route. Objective: The used engine oil was as the dielectric fluid with the objective of obtaining wealth from waste. The experiments were performed by varying distinct Electric Discharge Machining (EDM) process parameters with the goal of obtaining a high Material Removal Rate (MRR), low Tool Wear Rate (TWR) and least Surface Roughness (Ra). The experimental runs were optimized using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) optimization techniques. Methods: Experimental runs were designed using the L20 Taguchi orthogonal array in which Powder concentration, Current and Pulse on time were varied for three different levels, and two various dielectric fluids were used for investigation. The characteristics of the Used Engine Oil (UEO) were assessed to find its feasibility as a dielectric fluid. Results: In comparison to EDM oil, the specimen machined in UEO dielectric medium has a somewhat greater MRR. Regardless of the kind of dielectric fluid employed, adding Al2O3 particles increases the MRR because of the bridging effect. Due to its high thermal conductivity, UEO oil produced electrodes with a TWR that was greater than that of EDM oil. The TWR decreases with the addition of Al2O3 particles due to an increase in the spark gap. In comparison to EDM oil, the specimen machined under UEO displays a lower Ra value. Ra decreases with the inclusion of Al2O3 particles due to the thorough flushing of machining waste. Conclusion: The specimen machined under Al2O3 mixed UEO dielectric medium, with the process parameters tuned at 3A current and 20µs Ton, offers better machining performance and was recommended for EDM sector.