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This paper aims to cover the recent (2010-2016) techniques for carrying out hardness evaluation on lead-free solders. Details testing configuration/design were compiled and discussed accordingly to each of the measurement techniques: Vickers microhardness, Brinell microhardness and nanoindentation.

A brief introduction on lead-free solders and the concept of hardness testing has been described at the beginning of the review. Equipment setup, capabilities, test configuration and outcomes were presented for each technique and discussed in parallel along with the case studies from selected articles.

Comparison, outcomes and insight regarding each of the methods were highlighted to observe the recent trends, scientific challenges, limitations and probable breakthroughs of the particular hardness testing methods.

The compilation of latest reports, technical setup plus with the critics and perception from the authors are the main key value in this review. This provides an in-depth understanding and guidance for conducting hardness evaluation on lead-free solders.

The purpose of this study is to explore the importance of vibrations during welding process. In recent years, welding has gained its supremacy in the field of production. The main set back of the welding process is induced residual stresses, which is a major cause for many welding defects. These defects can be minimized by post-weld heat treatment methods, which is a time consuming and laborious process. In the recent past, a technique of exciting the weld-pool by vibrating the work-pieces was also adopted to minimize the above-mentioned stresses. A novel technique of electrode vibration is another effective way of transferring the vibrations to the weld-pool to influence the induced residual stress.

In this research, the electrode is vibrated with the help of an electric motor. The specimens were prepared as per American Society for Testing and Materials standards and welded with varying frequencies and voltages. The weldments are tested for hardness along the weld bead and heat affected zone, also the microstructure of the fusion zone is analyzed.

It is observed that there is an improvement in the hardness because of the grain refinement, which is a result of proper excitation of the weld-pool. It is observed that there is an improvement in hardness test up to 28.69% when compared with the conventional welding process. The peak value of hardness is observed at a frequency of 4,450 Hz. This is because of fine grain structure at this frequency, which is observed through the microstructure analysis.

A novel technique is introduced to refine the weld-pool through electrode vibrations. To improve the hardness of the welded joints, vibrations play a major role by refining the grain structure. The vibrations are imparted with the help of a special equipment attached to the electrode.

THE Rockwell hardness number is based on the additional depth to which the penetrator is driven by a heavy load beyond the depth to which the same penetrator has been driven by a definite light load. A minor load is applied and often, without moving the specimen, a major load is applied. The major load is then removed leaving the minor load on, and the hardness number is indicated on the dial.

The aim of this study is to present an experimental research on a Al₂O₃ · TiO₂ plasma coating on AISI 316 stainless steel substrate with and without SiC particulate reinforcement to show how SiC particulate effect on the hardness, wear resistance and microstructure of the coating.

The main objective of the paper is to investigate the effect of SiC particulate on the coating properties such as hardness, wear resistance and microstructure. Achieving of this purpose, harness and sliding test, surface roughness measurements were carried out. In addition to that parallel work on microstructural examination by optical microscope were also conducted. Owing to SiC particulate is harder than Al₂O₃ · TiO₂ plasma coating, it influence hardness and tribological behavior and result in increasing in hardness values and wear resistance of the coating reinforced with SiC particulate compare with unreinforced Al₂O₃ · TiO₂ plasma coating.

This study provides experimental results about the Al₂O₃ · TiO₂ plasma coating with and without SiC_p reinforcement. The obtained experimental results indicate that SiC_p in the coating is influence hardness, wear resistance and microstructure of the coating and make them much harder and having wear resistance. This result is consisted with the values obtained previous studies that is available in literature.

SEM or TEM studies may be needed for better understanding of wear mechanism. Various percentage of SiC particulate in the coating can be used in the further researches and provide more detailed information about effecting on SiC_p reinforcement of the coating.

The results show that SiC_p reinforcement contribute increasing in hardness and wear resistance of the coating. Those compositions of the coating can easily used in related industrial applications.

This paper fulfils some useful information about SiC_p Al₂O₃ · TiO₂ plasma coating and offers practical help to students, related academicians and researchers in the industry.

A method extensively used in the production of optically flat and finely finished surfaces is that of lapping the surface upon a plate using a loose abrasive mixed into a slurry form with a carrying fluid. If the surfaces finished in this way are in continuous or intermittent sliding contact, it is the author's opinion that any abrasives retained in their surfaces will affect surface wear. This paper reported on some exploratory work to indicate the degree of embedment of abrasive in certain materials lapped by hand.

The aim of the research is to investigate wear performance of some phenolic composites with boric acid.

The brake lining which has new formulation has been produced by using various additive materials. Various techniques have been used in the production of brake lining. These phenolic composites were subjected to friction and wear tests under different loads, and changes in the hardness and microstructures were examined.

As a result of this study, the following findings are reported. It was not found a direct proportionality between hardness and wear resistance due to the complexity of composite structure. Heat treatment application changed the microstructure of the brake lining, and increased the hardness and also decreased the density. With the increasing of temperature, the ingredients in the braking pad were affected other due to faster diffusion. On the other hand, hardness of specimen increases due to heat treatment and also specific wear ratio changes. As a filling material, barite was used due to better performance in the environmental conditions. More wear was observed in the bigger powder particles comparing to the smaller ones due to more structural loss. Squealing was heard in fiber un‐reinforced brake lining due to more barite content. In the present samples, boric acid deports the water and establishing the structural equilibrium. Therefore, these samples supplied higher and stable friction of coefficient. Also, heat treatment supplied a stable friction coefficient. With the increasing of copper powder into specimens, friction coefficient also increased. Heat treatment made the increment of hardness of specimens and also it made effect on the hardness with strengthening bonds of interparticles.

Limitations in the present research are as follows: two different pressures and eight different temperatures were used and brake linings were subjected to wear test, hardness tests, microstructures were examined.

For future work, instead of buying expensive brake lining, new and cheaper phenolic linings are produced. By this process, economic benefit can be gained and also environmental protection can be succeeded in producing such asbestos free brake linings.

This paper fulfills an identified information and offers practical help to the industrial firms working with brake lining and also to the academicians working on wear of materials.

A common procedure for processing stereolithography epoxy injection molds includes a one hour post‐cure in a UV chamber. This research investigates the degree of cure achieved in the UV chamber and the degree of cure achieved by heating in a thermal oven. It is hypothesized that a more fully cured mold is harder and hence will produce more parts before failure. This research investigates various post‐cure processes and suggests a post‐cure strategy to achieve this end.

The paper aims to examine the mechanical and wear performance of A356/Al₂O₃ (alumina) nanocomposites. The correlation between wear performance and the microstructural properties that result from various mechanical milling periods was investigated.

The production of nano alumina reinforced (1 Wt.%) A356 aluminum nanocomposite specimens was carried out using the traditional powder metallurgy method, incorporating three different mechanical milling times (1, 2 and 4 h). Subsequently, mechanical and wear performance assessments were conducted using hardness, compression and pin-on-disc wear tests.

Although the specimens subjected to the most prolonged mechanical milling (4 h) demonstrated superior hardness and compressive strength properties, they exhibited a remarkable weight loss during the wear tests. The traditional evaluation, which supports that the wear performance is generally correlated with hardness, does not consider the microstructural properties. Since the sample milled for 1 h has a moderate microstructure, it showed better wear performance than the sample with higher hardness.

The originality of the paper is demonstrated through its evaluation of wear performance, incorporating not only hardness but also the consideration of microstructural properties resulted from mechanical milling.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2023-0031/

Paper aims to an alloy development study was carried out to increase the mechanical properties of cylinder heads.

AlSi12 alloys are used to manufacture the compressor head cylinder by high-pressure casting for easy casting and superior properties. Therefore, 1.1%, 2.4% and 3.1% Mg were added to AlSi12. The microstructures of the produced samples were characterized by optical microscope, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction methods. Hardness and tensile tests as well as Charpy impact tests were performed. Wear tests were also carried out on the pin-on disc tester, and then the wear performance was examined on the tester, which simulates the actual operating condition.

AlSi12 has primary Si and eutectic Si in the Al matrix. However, alloys of Mg with AlSi12 have other intermetallics such as Mg₂Si and ß-Fe, as well as primary Si and eutectic Si. Hardness and tensile strength as well as improved wear performance with increased Mg content.

In this study, wear performance test to simulate the operation of the cylinder head produced by high pressure casting from AlSi12 alloy moreover tensile test, hardness test and impact test were performed. Therefore, in this study, the wear performance of the compressor head produced by high-pressure casting method by adding three different amounts of Mg to AlSi12 alloy was investigated.

The limitation of bridges’ operation can cause serious social, environmental and economic losses. Therefore, the monitoring and maintenance actions of these structures must be efficient and periodic, especially for bridges located in aggressive environments, such as urban-industrial centres, where the higher volume of carbon dioxide emissions favours carbonation induced corrosion. The purpose of this paper is to analyse the utility of including non-destructive testing (NDTs) to bridges assessment in that regions as a way of obtaining more in-depth information on the conditions of the material composing the structure.

First, the main bridges’ damages were detected by visual inspection. Then, based on the observations of bridges design, environment and main damages, an NDT programme was executed including surface hardness, ultrasonic pulse velocity test, pH indicator spraying, half-cell potential measurements and concrete resistivity tests.

It was observed that, for the studied cases, the carbonation did not present harmful depths, except for the structural elements where segregation and wear of the concrete were noticed. NDTs, associated with visual inspection, indicated the regions where corrective or preventive maintenance actions were actually needed, bringing greater security to the decision maker in regions where repairs are unnecessary or could be postponed.

This paper highlights the contribution of NDTs application in structures in urban-industrial regions where the main mechanism of deterioration is carbonation-induced corrosion, demonstrating the importance of these methods in the rational decision making of investments for maintenance.