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The aim of this paper was to determine fitting parameters in grain density of the magnesium primary phase function in AZ91/SiC composite heterogeneous nucleation model. Nucleation models have parameters, which exact values are usually not known and sometimes even their physical meaning is under discussion. Those parameters can be obtained after statistical analyze of the experimental data. Specimens of fourteen different composites were prepared. The matrix of the composite was AZ91 and the reinforcement was SiC particles. The specimens differs in SiC particles size (10 μm, 40 μm, 76 μm) and content (0 wt.%, 0.1 wt.%, 0.5 wt.%, 2 wt.%, 3.5 wt.%). They were taken from the region near to the thermocouple, to analyze the undercooling for different composites and its influence on the grain size. The specimens were polished and etched. The mean grain size for each specimen was measured. Specific undercooling for each composite was found from characteristic points on cooling rate curve. Microstructure and thermal analyze gave set of values that connect SiC particles content, their size and alloy undercooling with grain size. Those values were used to approximate nucleation model adjustment parameters. Obtained model can be very useful in modelling composites microstructure.

Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO₂).

In this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO₂ and AZ91D – (WC + SiO₂) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus.

Results showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO₂ particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO₂) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO₂ particles. Hence, the proposed AZ91D – (WC + SiO₂) composite could be a suitable candidate to be used in the aviation applications.

This work is original which deals with the effect of hybrid particles, i.e. WC and SiO₂ on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.

This paper aims to determine the optimum parametric settings for yielding superior mechanical properties, namely, ultimate tensile strength (UTS), yield strength (YS) and percentage elongation (EL) of AZ91D/AgNPs/TiO₂ hybrid composite fabricated by friction stir processing.

An empirical model has been developed to govern crucial influencing parameters, namely, rotation speed (RS), tool transverse speed (TS), number of passes (NPS) and reinforcement fraction (RF) or weight percentage. Box Behnken design (BBD) with four input parameters and three levels of each parameter was used to design the experimental work, and analysis of variance (ANOVA) was used to check the acceptability of the developed model. Desirability function analysis (DFA) for a multiresponse optimization approach is integrated with response surface methodology (RSM). The individual desirability index (IDI) was calculated for each response, and a composite desirability index (CDI) was obtained. The optimal parametric settings were determined based on maximum CDI values. A confirmation test is also performed to compare the actual and predicted values of responses.

The relationship between input parameters and output responses (UTS, YS, and EL) was investigated using the Box-Behnken design (BBD). Silver nanoparticles (AgNPs) and nano-sized titanium dioxide (TiO₂) enhanced the ultimate tensile strength and yield strength. It was observed that the inclusion of AgNPs led to an increase in ductility, while the increase in the weight fraction of TiO₂ resulted in a decrease in ductility.

AZ91D/AgNPs/TiO₂ hybrid composite finds enormous applications in biomedical implants, aerospace, sports and aerospace industries, especially where lightweight materials with high strength are critical.

In terms of optimum value through desirability, the experimental trials yield the following results: maximum value of UTS (318.369 MPa), maximum value of YS (200.120 MPa) and EL (7.610) at 1,021 rpm of RS, 70 mm/min of TS, 4 NPS and level 3 of RF.

This study aims to minimize pollution and enhance the mechanical properties of SiC- reinforced aluminum- based composite by utilizing waste eggshell. Pollution is increasing at an exponential rate across the globe. Every nation is struggling to have strong control over the rise in pollution. Many countries are even successful in this regard, but only up to a certain extent; also, a lot of capital investment is required just to make arrangements for making and taking care of dedicated dump yards. An alternative approach in this regard could be using the unwanted wastes in some constructive works by recycling them. Novel strategies and dedicated cells for the research and development regarding the recycling of various kinds of wastes are continuously being developed by various nations.

This study attempts to make a hybrid composite of AA6101 alloy through the friction stir process (FSP) technique in which waste eggshells and SiC have been used as reinforcement particles. As the densities of eggshells, SiC show different values of densities to make them a single entity, they were subjected to ball milling for around 75 h. After ball milling, the reinforcement particles (eggshells and SiC) were distributed uniformly in the metal matrix (Al), and they appear as a single entity in the metal matrix composite.

The main objective of this study is to obtain an enhanced value of tensile strength of the final composite. Concerning this, the parameters of FSP, i.e. rotational speed and transverse speed, have been optimized through the Box–Behnken design approach. The optimized values of FSP parameters came out to be as 935.92 rpm of rotational speed and 22.48 mm/min as transverse speed value.

The results showed that the tensile strength and hardness of the composite developed at an optimum combination of FSP parameters enhanced by about 47.14 and 45.45%, respectively.

In recent days, friction stir processing (FSP) has emerged as a pioneering approach for the manufacture of composites with enhanced mechanical and tribological properties. The present study aims to examine the impact of process parameters such as tool rotation speed and number of FSP pass on the AZ61A/TiC magnesium metal composite for responses such as hardness and wear resistance.

To minimize number of experimental runs, design of experiment was configured according to the response surface methodology using central composite design. Analysis of variance has been conducted to develop mathematical and empirical model for studying relationship between tool rotation and number of pass for responses such as microhardness and wear resistance. Microhardness was checked on vickers microhardness testing machine, and tribological behavior were examined on pin-on-disc using tribotester. Wear morphology was analyzed via scanning electron microscopy.

The responses were predicted using validated mathematical model, and contour plots were generated to study the interaction and influence of process parameters. Wear observations suggest that for the base magnesium alloy adhesive wear mechanism was dominating and for the developed nanocomposites, abrasive wear mechanism is a prominent factor. It was also observed that both the selected parameters significantly influenced the responses.

To the best of the authors’ knowledge, no prior work has been conducted with this material and preparation of composites with TiC nanoparticles. Furthermore, no mathematical models have been developed to predict the response values.

Friction stir processing (FSP) is overviewed with the process variables, along with the thermal aspect of different metals.

With its inbuilt advantages, FSP is used to reduce the failure in the structural integrity of the body panels of automobiles, airplanes and lashing rails. FSP has excellent process ability and surface treatability with good corrosion resistance and high strength at elevated temperatures. Process parameters such as rotation speed of the tool, traverse speed, tool tilt angle, groove design, volume fraction and increase in number of tool passes should be considered for generating a processed and defect-free surface of the workpiece.

FSP process is used for modifying the surface by reinforcement of composites to improve the mechanical properties and results in the ultrafine grain refinement of microstructure. FSP uses the frictional heat and mechanical deformation for achieving the maximum performance using the low-cost tool; the production time is also very less.

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