This paper aims to study the feasibility of friction stir welding of thermoplastic material polyamide 6,6. The maximum joint strength achieved through the optimized process variables is 41 MPa. The maximum temperature rise of 126 °C is achieved and the weld nugget exhibits a hardness of 69 D on Shore hardness scale. Fractography analysis reveals that the fracture followed a continuous plastic flow comprising less prominent fibrillation and more elongated voids. An increase in glass transition temperature Tg is observed in the weld specimen. The impact of the welding process variables on the frequency and band shift of the functional groups of the polymer is also discussed.

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This paper deals with the work done on friction stir welding of thermoplastic material PA 6,6. A specially designed welding tool was used for this polymer. The major process parameters like tool rotational speed, feed rate were varied to understand the physical changes of the polymer and to carry out characterization studies. In this study, an attempt was made to optimize the process parameters by using L9 orthogonal array approach. ANOVA analysis was used to explore the effect of process parameters. Tensile testing was performed to analyze the joint strength. Thus, in new exploration of using polyamide 6,6 as base material, a maximum joint strength of 37 MPa has been achieved. Optimum combination of process parameters were found by using ANOVA studies. Microstructure of the friction stir welded joints using scanning electron microscopy was done. The X-ray diffraction and the thermogravimetric analysis were done to determine the degree of crystallinity and the level of degradation of the friction stir welded joints.

The friction stir welding of polyamide 66 with a specially modified tool is studied. A variation of the conventional friction stir welding is investigated by incorporating a friction plate for the purpose of heating the polymer in the course of welding process through the tool shoulder. This in turn, improves the efficiency of the weld. The association of the welding process parameters and the weld performance has been investigated by the grey relational analysis with multi response characteristics like weld tensile strength, percent elongation and hardness. Macrostructure of the weld joint cross section has been explored by Stereo microscope. The maximum weld tensile strength of 63 MPa and a Shore hardness of 60 D at the weld nugget are obtained. The hardness profiles of the welded samples have been analyzed in this investigation.

People are implanted or clipped with orthodontic wires made of diverse materials in order to regulate the growth of teeth. When these orthodontic wires are exposed to the oral environment, by the influence of food intake, toothpaste, mouthwash and tablets, may undergo corrosion. The present study focus the evaluation of corrosion resistance action of orthodontic wires of Ni-Ti alloy immersed in artificial saliva in the absence and presence of Domperidone and Perinorm tablets. Polarization and AC impedance study reveals that the corrosion rate of the Ni-Ti alloy system in various solution decreases in the following order: Artificial Saliva > Artificial Saliva + Domperidone / Perinorm tablet. This is evidenced by gradual increase in Linear Polarization Resistance (LPR) and decrease in Corrosion Current (Icorr) by polarization studies then there is an increase in charge transfer resistance (Rct) and decrease in double layer Capacitance (Cdl) by AC impedance spectra. Scanning electron microscope imaging gave the morphological data for the sample; however using the Scanning electron microscope and Energy Dispersive Analysis of X-Rays the elemental composition was determined. Hence the present study concludes that people clip with orthodontic wire made of Ni-Ti alloy can take Domperidone / Perinorm tablets orally without any hesitation.