Papers by Author: S. Abdi

Abstract: The present investigation attempts to understand the friction welding characteristics of Aluminum alloy AlCu and steel AISI 4140. In spite, many trials were applied to achieve the sound weld zone of direct bonding between Aluminum and steel. The formation of intermetallic phase and crack in the near weld zone resulted in a lower tensile strength of joints relative to those of other welding technique. Therefore, to prevent intermetallic phase and crack formation at the interface, pure copper was used as insert powders for stress relief buffer layer. This study also envisages the influence of process parameters which include resident preform densities, friction pressure, upset pressure, and burn-off length on microstructure and mechanical properties of the welds. This work consolidates information on the aspects of diffusion joining of steel, copper and Aluminum component with wrought materials for practical execution. In the view point of tensile strength, the highest tensile strength between AlCu and AISI 4140 was acquired by using pure copper as insert powder.

Abstract: The object of the present work is to study the spraying of poly-powders nickel bases containing Cr, Si, C and B elements addition with variable percentage of iron, deposited on a steel substrate by oxy fuel thermal spraying. The substrate surface was previously treated by Al–Ni bond coat and post–annealing at 650°C. The spraying powder and coating micro structure were investigated by combination of X-ray diffraction, electron microprobe and scanning electron microscope coupled to an analyzer energy dispersive x-ray. The adherence to substrate was determined by using shear test for adhesion. The result of this study was to investigate to compare potentials of HVOF sprayed NiCrBCSi and satellite 6 coating for a possible to replacement of hard chromium plating. A good adherence of coating NiCrBCSi (Fe) on steel substrate is explained by formation of large diffusion zone in interface after annealing and by the nature of the structure deposit duplexes.