Interest in natural fiber–reinforced composites (NFRCs) is increasing rapidly thanks to their numerous advantages such as low cost, biodegradability, eco-friendly nature, relatively good mechanical properties, and a growing emphasis on the environmental and sustainability aspects of engineering materials. However, large-scale use of NFRCs is still considered as challenging due to the difficulties in manufacturing, limited knowledge of its machinability and appropriate parameter settings, and being prone to machining-induced defects. This article presents a comprehensive review on various aspects of NFRCs, with a focus on the manufacturing and machinability. It covers some recent works related to NFRCs, including the manufacturing processes and parameters, characterization of mechanical properties, applications, and machinability and machining process monitoring, many for the first time. The main challenges associated with machining of NFRCs and the induced damages are outlined, with special attention paid to the effect of physical properties of the fibers and manufacturing process on the machinability, along with the essential machining parameters that affect the quality of the machined surface. The research perspectives and the current application status are also discussed. The article is intended to help readers attain a fundamental understanding of key technologies and the state of the arts in this research area.

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This paper aims to investigate the effects of machining parameters such as spindle speed, feed rate and drill diameter on machinability of flax/poly(lactic acid) bio-composites, to analyze the relations among cutting forces, drillinginduced damages and crack propagation of the drilled samples. In particular, a set of drilling experiments were conducted using different drilling conditions and a new low-cost measurement set-up was developed to measure the cutting force during the drilling operation. In addition, the analysis of variance (ANOVA) was applied to identify the significance of each individual cutting parameter. The experimental results indicate the relation between the thrust force and the machinability parameters of flax fiber reinforced bio-composite.The increase in spindle speed reduces thrust force and delamination size of the drilled holes, whereas an increase in feed and drill diameter leads to a considerable increase in both thrust force and delamination factor. The effect of spindle speed on peripheral damage was not significant for the drills tested, though the feed rate was found to play the key role on the delamination damage area. The best hole quality was achieved with the samples drilled at spindle speed and feed rate of 3000 rpm and 0.11 mm/rev, respectively.

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In this paper the composite of alloy Al-5%Cu alloy reinforced with different percent of В 4 С (average size of 5 microns) have been prepared using stir casting technique. This technique found to be effective for giving uniform distribution of В 4 С particles through the matrix. Increasing the content of В 4 С particles in the matrix alloy leads to a minor porosity increase from 1 % to 3.1 %. The average linear thermal expansion coefficient in the temperature range from 20 to 100 °C decreases from 24.5 to 22.6 10-6 °C-1 .