Examinando por Autor "Abu-Warda, Najib"

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Influence of the surface state on the corrosion behavior of the 316 L stainless steel manufactured by laser powder bed fusion
(Elsevier, 2022) Bedmar, Javier; Abu-Warda, Najib; García Rodríguez, Sonia; Torres, Belén; Rams, Joaquín
The effect of surface roughness on the corrosion behavior of 316 L stainless steel manufactured by LPBF has been evaluated. The behavior of the steel in the as-built state was compared to that ground up to 2500 grade. Three different aggressive environments were used: 3.5 wt% NaCl water solution, 3 wt% H2SO4 solution, and hightemperature oxidation at 800 ºC. The ground specimens showed higher corrosion resistance. The corrosion resistance was much smaller in the as-built samples for electrochemical tests, and the lowest mass gain after hightemperature oxidation was found in the ground specimens.
The effect of TiB2 content on the properties of AA6005/TiB2 nanocomposites fabricated by mechanical alloying method
(Elsevier Science Bv, 2018) Abu-Warda, Najib; Utrilla, María Victoria; Escalera, María Dolores; Oterp, Enrique; López, María Dolores
An A6005 aluminium alloy composite reinforced with different contents of titanium boride particles (2.5, 5 and 10 wt%) was produced by a mechanical alloying (MA) route. First, the aluminium alloy and titanium boride powders were blended by MA at different milling times, from 1 to 10 h. The samples obtained after MA processing were microstructurally and mechanically characterised by OM, SEM, TEM, LDS, XRD and micro-hardness tests. The optimum size distribution and suitable mechanical properties were obtained with 5 or 10 wt% of titanium boride particles after 8 h of MA, when the steady state is reached. Hot extrusion was employed as a consolidation process. An extruded sample of powders with a 5 wt% reinforcement content that was MA for 8 h was characterised by TEM, FE-SEM and nanoindentation tests. The results show a good distribution of the nano-reinforcement within the aluminiummatrix. Nano-indentation test shows an increment in hardness values from2.6 GPa for the reference extrusion of A6005 powderswithout MA and reinforcement to 3.3 GPa for the A6005 extrusion with 5 wt% TiB2 and MA for 8 h.