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In the present research, our aim is to study effects of alfa fiber content, alkali, maleic anhydride grafted polypropylene (MAPP), and the combined treatment (alkali and MAPP) on the tensile and flexural behavior of alfa fiber-reinforced polypropylene (PP) composites. These composites were produced using a single-screw extruder followed by an injection molding process. Both fibers and composites were characterized using optical and SEM microscope in order to evaluate the interfacial adhesion between the fibers and the matrix. From the main results, the tensile modulus and flexural strength of 30% untreated Alfa fiber/PP composites were found to increase significantly compared to those of PP. Meanwhile, there is no significant increase in terms of the tensile strength and the flexural modulus. Moreover, the composites with a combined treatment have shown significant effect on the tensile and flexural properties compared to untreated composites and the treated ones. The SEM observation of the morphology of alkali treated fibers exhibited an increase in the surface roughness because the removal of impurities. In addition, SEM photos of the fractured surface of composites reveal the improvement of the fibers and PP matrix interface quality by treatments, in particular the combined treatment. [ABSTRACT FROM AUTHOR]

AbstractIn this study, the influence of the applying repeated thermal cycling during welding on the microstructural transformations and mechanical properties in Austenitic Stainless Clad-Steel Plates (ASCSP) has been investigated, particularly in the substrate. For this purpose, a novel methodology was used, by filling the entire groove length and gradually shortening the subsequent passes. Afterwards, microstructural characterization of different zones in the welded joint was conducted using optical microscope. Results showed a decrease in acicular ferrite (AF) in the Weld Metal Substrate (WM-S) from the root pass (10 kJ/cm) to the second pass (13.5 kJ/cm). This decrease continued until a total disappearance by the third pass due to a heat input of 17.8 kJ/cm. Vickers micro-hardness test was used to investigate the effect of the subsequent passes on the mechanical properties of the joint. Micro-hardness examination confirms the metallurgical results. It was revealed that micro-hardness variations are influenced by AF percentage and pro-eutectoid ferrite levels. [ABSTRACT FROM AUTHOR]