Abstract The present work is focused on the influence of zinc trivalent plating on laser shot peened AISI 304 stainless steel samples to improve the corrosion resistance of the steel surface. AISI 304 steel samples were heat treated by annealing and polished to perform Laser Shot Peening (LSP) process using Nd-YAG laser functioning at a pulse interval of 10ns with different energies of 200 mJ, 300 mJ and 400 mJ on each sample. The highest magnitude of compressive residual stresses is induced using the pulse density of 2500 pulses/cm2. The laser treated sample was characterized by surface hardness using Vickers micro hardness test and surface morphology using an optical microscope and SEM analysis. The surface hardness of the sample is increased by increasing laser energy. The prepared zinc trivalent is plated using electro deposition on the laser treated surface by maintaining current between 1.5 to 4 amps/Dm2, and temperature between 20 to 40 deg C. MAHR’s roughness tests were performed to find the surface roughness of the sample. The surface roughness has drastically increased on zinc- coated samples compared to samples without coating. The Vickers micro hardness test conducted on zinc trivalent plated sample revealed the increase in hardness value of 200 mJ by 24% compared with 200 mJ sample without coating. SEM and EDAX were carried out to know the changes occurred in the chemical composition of the samples before and after coating.

Franck-Condon factors (vibrational transition probabilities) and r-centroids have been evaluated by a numerical integration procedure for the bands of A 0+g - X ¹sigma+, B 0+g - X ¹sigma+ systems of AuH and A 0+ - X ¹sigma+ system of AuD molecules using a suitable potential. The physical and astrophysical significances of our evaluated Franck-Condon factors and r-centroids have also been discussed, which would be helpful in the prediction of the presence of AuH and AuD molecules in various celestial bodies.

The deformation response of magnesium based metal matrix composite was investigated by means of hot compression tests. The flow curves were obtained in the temperature and strain rate range of 300-500 °C and 0.001-1 s-1 respectively in order to obtain the processing maps of the studied material and interpreting them on the basis of the dynamic material model. Micro-structural characterization studies conducted on the deformed composite samples, using optical and scanning electron microscopy, revealed a recrystallized grain morphology, debonding of Titanium particles, particle breakage and cracking of the matrix. The observations were performed in order to describe the behavior of the material under hot forming operation in terms of material damage and micro- structural modification.