Laser surface hardening (LSH) is one of the most widely used surface hardening process which can be applied to almost the whole range of metallic materials in today's applications. Laser beam is focused to the localised region for hardening the required portion of the material. High intensity laser radiation is involved for heating the surface of steel into the austenitic region. Steep temperature gradient arises, due to high rates of heat transformation that results in instant cooling by conduction. It causes the phase conversion from austenite to martensite without the need for external quenching. Among various types of lasers, CO

In the past few years, a new passion for the growth of biodegradable polymers based on elements derived from natural sources has been getting much attention. Natural fiber-based polymer matrix composites offer weight loss, reduction in cost and carbon dioxide emission, and recyclability. In addition, natural fiber composites have a minimal impact on the environment in regards to global warming, health, and pollution. Polylactic acid (PLA) is one of the best natural resource polymers available among biodegradable polymers. Natural fiber–reinforced PLA polymer composites have been extensively researched by polymer researchers to compete with conventional polymers. The type of fiber used plays a massive part in fiber and matrix bonds and, thereby, influences the composite’s mechanical properties and thermal properties. Among the various natural fibers, low density, high strength bamboo fibers (BF) have attracted attention. PLA and bamboo fiber composites play a vital character in an extensive range of structural and non-structural applications. This review briefly discussed on currently developed PLA-based natural bamboo fiber–reinforced polymer composites concentrating on the property affiliation of fibers. PLA polymer–reinforced natural bamboo fiber used to establish composite materials, various composite fabrication methods, various pretreatment methods on fibers, their effect on mechanical properties, as well as thermal properties and applications on different fields of such composites are discussed in this study. This review also presents a summary of the issues in the fabrication of natural fiber composites.

An experimental investigation with Nd:YAG laser system was carried out to study the effects of laser hardening process parameters on the microstructure and hardness during laser hardening of EN25 steel. The laser beam is allowed to scan on the surface of the work piece by varying the laser beam power (750–1250 W) and travel speed (500–1000 mm/min) of the work table. The microstructural features of the laser hardened EN25 steel were analysed using optical microscope. The microstructure of the surface layer was found to consist of plate martensite. A substantial increase in surface hardness was achieved, by a factor of 2 times the base material hardness.

The utilization of composite materials has nowadays increased in aerospace applications due to their less weight and superior mechanical properties. Nevertheless, machining of composite materials without damage is quite challenging through conventional system due to their inherent heterogeneity, anisotropy, and thermal sensitivity. To overcome this problem, abrasive water jet machining process can be employed. It is a non-conventional machining processes with high accuracy, high flexibility and with no heat generation. However, there are more challenges in cutting fiber reinforced plastics with this technique. Hence, this work deals with the assessment of the optimum process parameters in abrasive water jet cutting of carbon fiber reinforced plastic composite. Cutting experiments were conducted by varying input parameters such as the traverse rate, standoff distance on three laminates of different thickness. Analysis of variance through response surface methodology technique was used to study the effect of each input parameters on the output responses such as kerf taper and surface roughness. Optimum parameters that provide the best machining quality were found using numerical and graphical optimization techniques. The results showed that increasing the traverse rate results in increased surface roughness and taper angle of the cut kerf. Hence lower traverse rate is preferable when machining quality is of high importance.