P. Samadi, M. Reza Afshar, M. R. Aboutalebi, S. H. Seyedein,
Volume 9, Issue 1 (3-2012)
Abstract
Electrochemical coating processes are significantly affected by applied magnetic fields due to the generation of electromagnetic forces. The present research work has been undertaken to study the effect of coating parameters such as current density and alumina concentration on the characteristics of Ni-Al2O3 composite coating under static magnetic field. Ni-Al2O3 composite coating was applied on a mild steel substrate using conventional Watts solution containing Al2O3 particles with and without magnetic field. The coating microstructure and Al2O3 particle density in the coating layer were examined by scanning electron microscopy (SEM). It was found that the applied magnetic field made the coating structure finer and leads to the increases of the particle content in the coating. However, the results confirmed that the magnetic forces inversely affected the particle density in the coating at higher current density than that of normal coating process.
Z. Sadeghian, R. Dezfulizadeh,
Volume 13, Issue 2 (6-2016)
Abstract
In situ Al2024- Mg2Si composite was fabricated by spark plasma sintering (SPS) of reactive powder. Reactive powder was obtained from mechanical alloying (MA) of elemental powders. Clad layers of in situ composite were fabricated on Al substrates by spark plasma sintering (SPS). Structural evolution during MA process and after SPS was investigated by X-ray diffractometery (XRD). Scanning electron microscopy (SEM) was utilized to study the microstructure of sintered samples. Hardness and tensile behavior of sintered samples were investigated. The results showed that SPS of mechanically alloyed unreacted powder can result in the in situ formation of Mg2Si and Mg2Al3 within the Al matrix. SPSed clad layer showed a sound and clear interface to the Al substrate with a hardness of about 140 HV. Sintered in situ composite exhibited a tensile strength of 288 MPa.
Mohammad Jafaripour, Hassan Koohestani, Behrooz Ghasemi,
Volume 18, Issue 4 (12-2021)
Abstract
In this study, aluminum matrix composites reinforced with Al2O3 and SiC nanoparticles, and graphene nanoplatelets produced by Spark Plasma Sintering (SPS) were studied. The microstructural and mechanical properties of the composites were evaluated by changing the amounts of the reinforcing materials. The SEM images showed that the reinforcing particles were more distributed in the grain boundary regions. According to the results, the addition of alumina and SiC to the matrix caused an increase in the composite density whereas the composite density decreased by adding graphene nanoplatelets. The highest relative density of 96.3% was obtained for the composite containing 2 wt% Al2O3. The presence of the reinforcing particles increased the hardness of all the samples compared to the pure aluminum (39 HV). The composite containing 1 wt.% Al2O3, 0.7 wt.% SiC, and 0.3 wt.% graphene showed the highest hardness of 79 HV. Moreover, the plastic deformation of the specimens decreased and the slope of the plastic region increased by adding the reinforcing particles to the matrix.
