Analysis of tensile strength, crystallinity, crystallite size, and thermal stability of polypropylene joined by friction stir welding

Abstract

This paper aims to investigate the joining of polypropylene using friction stir welding (FSW). FSW parameters were the rotation speed of 620 rpm, the travel speed of 7.3 mm/min, and 13 mm/min. The tensile test was performed using a universal testing machine, and the results of the tensile test were related to the crystallite size and degree of crystallinity. X-ray diffraction (XRD) was performed to examine the crystallite size and degree of crystallinity while thermal analysis was carried out using TGA/DSC. Besides, the effect of the degree of crystallinity on the thermal stability at the weld nugget area due to travel speed is explained in this paper. The findings showed that FSW with a travel speed of 7.3 mm/min had a higher crystallite size and degree of crystallinity than that with a travel speed of 13 mm/min, because there is a fusion of crystals and also recrystallization occurs, as an effect of the difference in the length of time exposed to heat during the FSW process. From the study results, it can be seen that the FSW with a 7.3 mm/minute travel speed has a higher crystal size and degree of crystallinity compare with the use of 13 mm/minute travel speed. The reason for that, the difference in heat exposure time during FSW affects crystal fusion and recrystallization. A sample with a travel speed of 7.3 mm/min had high tensile strength because it obtains sufficient heat for a more complete joint. In terms of thermal stability, the specimen with a lower travel speed showed a higher stability level than the specimen with a higher travel speed in that of the higher degree of crystallinity.

Evaluation of specific total work of fracture in polypropylene/ethylene‐propylene diene monomer nanocomposites based on various graphene derivatives: Optimization by response surface methodology technique and correlation with microstructure properties

“…The overlapping 131, 041, and 111 planes of α-type monoclinic crystal structure PP are also observed. [50,51] This evidence proves that PP/EPDM nanocomposites consist α-type monoclinic crystal structure. As can be seen from Figure 9 the WAXD pattern of TPE30F compared with the TPV30F specimen represents no change in the WAXD diffraction peak.…”

Dissimilar Joining of UHWMPE and PP Using Friction Stir Welding (FSW), and Mechanical Properties Evaluation.

“…Different efforts have been dedicated to investigate individually the FSW of these two thermoplastics, [25,[30][31][32]; nevertheless, no results are available for the joining using FSW, of these two dissimilar polymers.…”

Assessment of friction stir welding joints of AA2017-T4 aluminum by disc pressure mechanical tests

“…Since its advent in the 1990's at the welding institute (England), [1], the friction stir welding (FSW) has proven its efficiency in welding similar or dissimilar materials, which are known to be either difficult or even impossible to weld by other conventional fusion welding techniques. Examples of such materials are metallic alloys like aluminum, titanium [2] and copper or dissimilar materials like aluminum/magnesium, aluminum/copper, and aluminum/stainless steel [3] or even polymers, [4,5]. FSW is a solid-phase welding process that operates by plunging the pin of a specially designed rotating tool, made of harder material, between the materials to be welded, and fractioning these materials with the rotating tool, so as to generate enough heat for softening the materials and mix them to create the welding joint.…”