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The energy of a laser beam is generally calculated based on the laser power and its processing speed. In this work, the laser welding modes such as conduction, conduction—penetration, and keyhole welding of thickness 1.6, 2, and 2.5 mm AISI304 stainless steel sheets, respectively, are studied at different beam energy levels. A series of bead-on-plate trials are conducted using a 500 W continuous wave Nd:YAG laser source to study the beam—material interaction and the influence of laser power and welding speed on the formation of weld pool. In addition to the experimental study, a three-dimensional finite-element model is developed to analyse the transient heat flow and to predict the formation of the weld pool. The correlation among the parameters including laser power, welding speed, beam incident angle, and the characteristic geometry of weld pool are established. Temperature-dependent thermal properties of AISI304 stainless steel, the effect of latent heat of fusion, and the convective and radiative aspects of boundary conditions are considered in the model. The heat input to the developed model is assumed to be a three-dimensional conical Gaussian heat source. Finite-element simulations are carried out by using finite-element code, SYSWELD, and FORTRAN subroutines available within the code are used to obtain the numerical results. The result of the numerical analysis provides the shape of the molten pool with different beam energy levels, which is then compared with the results obtained through experimentation. It is observed that the results obtained from finite-element simulation and the experimental trials are in good agreement.

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Hybrid copper matrix composites containing 5 wt.% of titanium dioxide and varying graphite content (0 wt.%, 2 wt.% and 4 wt.%) were synthesized using powder metallurgy. Metallurgical studies were carried out to examine the presence and distribution of reinforcements in the copper matrix. To investigate the forming behavior of the sintered composite preforms, cold upset tests were conducted from which the true axial stress, the true hoop stress, the true hydrostatic stress and the true effective stress were evaluated and their relationship with the true axial strain was analyzed and presented. It is observed that the increase in addition of weight percentage of graphite into the copper matrix increases the true axial, the true hoop, the true hydrostatic and the true effective stresses. The variation of hardness, strength coefficient and strain hardening with respect to the addition of graphite content is also evaluated and reported.

In-situ aluminium alloy 8011 matrix composites containing different weight percentages of titanium diboride were synthesized by flux assisted synthesis using stir casting technique. The metallurgy of the in-situ AA8011-TiB2 composites was analyzed using X-ray diffractometer, scanning electron microscope and energy dispersive spectroscope to disseminate the formation and distribution of reinforcements. Density, microhardness and tensile strength of cast AA8011 and in-situ AA8011-TiB2 composites were measured and analyzed. The in-situ formed TiB2 reinforcements showed the maximum hardness of 55.03 Hv and the maximum tensile strength of 158.2 MPa for 8 wt. % of TiB2 whereas the percentage elongation of 7.2% is observed at 4 wt. % of TiB2. Further, the fractography analysis performed on the fractured tensile samples and the mechanism of failures were identified and reported.