Papers by Keyword: Metallisation

Abstract: The superalloy of Inconel 718 variety is widely used to produce compressor blade in gas turbine engine. The blade tip invariably wears in services and thus requires frequent metallization for repairing. In most commercial Turbine Engine Industries the metallised blades, after grinding, undergo a stress relieving heat treatment at 7600C before return for applications. In this study, the metallised blade is heat treated at different conditions and compared its microstructure and hardness with those of the standard stress relieving treatment blades used in most industries. The microstructure of the stress relieving sample contains dendrite with hardness of 230 HV for the melt zone, 190 HV for the Heat Affected Zone (HAZ) and 420 HV for the parent metal. Solutionising at 982 or 10660C developed hardness less than 220 HV in all sections. By long time ageing treatment of the solutionised sample developed high hardness across the whole blade. These treatments homogenized the microstructure and produced high hardness values by precipitation of secondary phase structures across the blade.

Abstract: The first principle investigations on electronic structure of ABC2 (A = Cd; B = Si, Ge, Sn; C= P, As) pnictides using the Tight Binding Linear Muffin Tin Orbital (TB-LMTO) method within the Atomic Sphere Approximation (ASA) is reported. Variation of Eg with pressure reveals the direct and pseudodirect natures of these compounds. CdSiP2 shows a pseudo direct and CdGeP2, CdSnP2, CdSiAs2, CdGeAs2 and CdSnAs2 show direct band gap natures. Semiconductor to metal transition at high pressures is observed. Metallisation volumes (V/Vo) m and pressures (Pm), bulk modulus (Bo) and its pressure derivative (Bo 1) are reported. Correlation connecting Bo and the unit cell volume (Vo) is established.