M. Arivarasu

Bio: M. Arivarasu is an academic researcher from VIT University. The author has contributed to research in topics: Corrosion & Welding. The author has an hindex of 12, co-authored 55 publications receiving 400 citations.

Investigations on structure–property relationships of activated flux TIG weldments of super-duplex/austenitic stainless steels

Abstract: This research work articulated the effect of SiO2 flux assisted tungsten inert gas (TIG) welding on the microstructure and mechanical properties of marine grade stainless steel weldments, such as super-duplex stainless steel (UNS S32750) and austenitic stainless steel (AISI 316L). The studies showed that the use of flux decreased the heat input required to obtain complete penetration. Microstructure studies revealed the presence of ferrite at the heat affected zone of AISI 316L and the fusion zone which obviated the hot cracking tendency. Tensile studies corroborated that the joint strength was sufficiently greater than that of the parent metals. Impact toughness slightly impoverished owing to the presence of large platelets of Widmanstatten austenite in the fusion zone. The study also explored the structure–property relationships of the flux assisted weldments using the combined techniques of optical and scanning electron microscopy analysis. Owing to the better metallurgical and mechanical properties, this study recommends the use of SiO2 flux for joining the dissimilar metals involving austenitic and super-duplex stainless steels.

Effect of Continuous and Pulsed Current on the Metallurgical and Mechanical Properties of Gas Tungsten Arc Welded AISI 4340 Aeronautical and AISI 304 L Austenitic Stainless Steel Dissimilar Joints

Abstract: In this research work, the weldability of low alloyed AISI 4340 aeronautical steel and AISI 304L austenitic stainless steel joined by continuous current (CC) and pulsed current (PC) gas tungsten arc welding (GTAW) techniques, using ER309L and ERNiCr-3 filler metals was investigated. The main focus of the study involves the investigation on the effect of continuous and pulsed current mode of GTA welding process on the metallurgical and mechanical properties of these dissimilar weldments. Microstructure studies revealed the formation of different zones across the weldments, vis-a-vis martensite at the HAZ of AISI 4340, vermicular δ - ferrite /ferrite stringers at the HAZ of AISI 304L, pearlite colonies at the parent metal of AISI 4340 and equi-axed cellular and/or columnar dendrites at the weld zone. Tensile results showed that current pulsing accrued better tensile properties. The structure - property relationships of these weldments were established based on the current modes employed by utilizing combined techniques of optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).

Numerical modelling of thermal phenomenon in friction stir welding of aluminum plates

Abstract: Friction stir welding (FSW) is a solid state welding process with potential to join materials that are non weldable by conventional fusion welding techniques. The study of heat transfer in FSW aids in the identification of defects like flash, inadequate heat input, poor material flow and mixing etc. In this paper, transient temperature distribution during FSW of aluminum alloy AA6061-T6 was simulated using finite element modelling. The model was used to predict the peak temperature and analyse the thermal history during FSW. The effect of process parameters namely tool rotation speed, tool traverse speed (welding speed), shoulder diameter and pin diameter of tool on the temperature distribution was investigated using two level factorial design. The model results were validated using the experimental results from the published literature. It was found that peak temperature was directly proportional to tool rotation speed and shoulder diameter and inversely proportional to tool traverse speed. The effect of pin diameter on peak temperature was found to be trivial.

Research and Development in Magnesium Alloys for Industrial and Biomedical Applications: A Review

Abstract: The work reviews the research and development status of magnesium alloy, with more attention to the methodologies and technologies adopted to improve the properties of AZ91 alloy. The drive force of utilizing magnesium alloys for automotive and biomedical application is light weightiness and biocompatibility respectively. However, the softness and high activity of magnesium alloys result in high wear and high corrosion rate respectively. One of the essential factors influencing the properties of magnesium alloy is its microstructure. Consequently, the grain size, morphology and distribution of phase constituents influence the properties of magnesium alloys. The modification of microstructure through processing route (hot working and cold working), heat treatment, and alloying elements improves the mechanical, corrosion, biocompatible, and tribological properties of magnesium alloys. Besides microstructural modification processes, addition of reinforcements, and coatings improves the properties of magnesium alloys. This article emphasis on the recent research on the technologies to improve the microstructure, hardness, tensile strength, ductility, yield strength, wear resistance, and corrosion resistance of magnesium alloy AZ91. Moreover, this review addresses the key issues hindering the applications of magnesium alloys for structural and biomedical applications.