Strength of Mg–3%Al alloy in presence of graphene nano-platelets as reinforcement

Bulk Mg–3%Al alloy-based nanocomposites containing graphene nano-platelets (GNPs) were synthesised using the powder metallurgy technique incorporating energy efficient hybrid microwave sintering and hot extrusion. GNPs in amounts of 0.1, 0.3 and 0.5?wt-% were investigated as reinforcements. Microstructural characterisation accomplished using optical, scanning and transmission electron microscopy revealed the presence of minimal porosity (<1%), a uniform distribution of GNPs in the matrix and a reduced grain size as a result of the presence of GNPs. The results of mechanical property characterisation revealed an overall improvement in micro-hardness and compressive response, due to the presence of GNPs, with best results exhibited by the Mg–3Al/0.3% GNPs composite. The ductility under compressive loading for composite samples remained higher than 20%.     

Drying of Agricultural Grains in a Multiple Porous Draft Tube Spouted Bed

A multiple porous draft tube spouted bed (MPDTSB) was used to carry out drying of Ragi (Eleusine coracana), Barley, and Wheat grains. Batch experiments were conducted under varied conditions of initial moisture contents of grains, air inlet temperatures, and airflow rates. The draft tube parameters and fluid inlet sizes were also varied in the study. The results indicated that MPDTSB has the potential to be used for scale up to large-scale solids drying. In addition, two single porous draft tube spouted beds (SPDTSBs) were used for comparison with MPDTSB; the batch drying times in the MPDTSB were found to be lower when compared to those in SPDTSB under identical operating conditions.     

Characterization of Joints Between Aluminum and Galvanized Steel Sheets

Sound joints between an AA6016 aluminum sheet of 1.2-mm thickness and a low-carbon galvanized steel sheet of 0.77-mm thickness are obtained using the laser pseudo-brazing method. A zinc-based aluminum alloy is used as a filler wire with optimized process parameters for laser pseudo-brazing. Metallurgical investigation of the joint is carried out using a scanning electron microscope and energy-dispersive X-ray analysis. Joints produced using Al-Zn filler wire showed a moderate strength and quality with a layer containing principally Fe₂Al₅Zn _x type intermetallics of ~10-μm thickness. Failure in the heat-affected zone of aluminum is found to be dominative, while in some cases, fracture along the interface between the intermetallic layer and the steel sheet is observed.