Rotary forming is a promising technique for high-volume, low-cost production of fuel cell components such as bipolar plates, but it needs to be better characterized for this application. In this paper, die design parameters in rotary forming of ultra-thin stainless steel 316 L sheets 100 μm thick are evaluated to explore how channels perpendicular and parallel to the rolling direction are affected by critical forming process parameters, namely depth of deformation, die corner radius, and friction coefficient. Channels are formed experimentally, and the results are used to verify the 2D and 3D simulations. The process is analysed in terms of die movement path and forming. Stress, strain, formed shape, and thickness are compared for the two main forming directions. Results showed that channels formed parallel to the rolling direction experience more plastic deformation and conform better to the prescribed geometry in terms of channel and flatness angles.

In this study, cubic coupons of AlSi10Mg alloy were printed using the laser powder bed fusion (LPBF) technique. The effect of heating/reheating cycles on solute trapping and partitioning of alloying elements was investigated using atom probe tomography and transmission electron microscopy. Nano-hardness analysis and uniaxial tensile tests equipped with digital image correlation were employed to investigate the mechanical properties and Poisson's ratio. X-ray micro-computed tomography was utilized to detect strain localization sites along the building direction. Also, the uniaxial tensile test was simulated using finite element analysis to verify the experimental data and predict stress triaxiality. The results showed that the solute trapping and partitioning during the LPBF process results in remarkable changes in phases, their size and morphology, Poisson's ratio, strengthening factor, and consequently mechanical properties. While the tensile sample from top part of the LPBF coupon mostly shows porosity due to floating and entrapment of gases during layer-by-layer fusion/solidification, the sample from bottom part is exposed to sub-surface microcracking induced by residual stresses. The hardness, elastic, and shear moduli, Peierls stress, and cumulative strain energy of the top-part sample are higher than those of the bottom-part sample even though electron backscatter diffraction analyses report similar grain size and texture. Besides, by distancing from the build plate, the Poisson's ratio decreases. Simulation results of both samples indicate that the middle of the gauge is a high-potential area of failure initiation, where the bottom-part sample shows higher stress localization.

Machining of metal matrix composites (MMC) is a challenging process as they are difficult to cut and cutting tools get worn out in a short time. In this paper, the performance of two industrial carbide grades and a cubic boron nitride (CBN) tool are assessed when machining of AZ91/SiC composites. Mg-based composites with different volume fractions and particle sizes are machined at various cutting conditions to evaluate the tools wear resistance and finished surface. The surface of the worn-out tools and machined samples are analyzed by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and roughness tester. Results revealed that the tool wear increased for composites reinforced by smaller particles regardless of the tool type. Additionally, tool grade TH1000 resulted in longer tool life when machining of Mg-based composites compared to the CP500 grade so that at a cutting speed of 70 m/min and feed rate of 0.1 mm/rev, tool life improved nearly 250%. CBN tools showed the best performance when machining of Mg-based composites as tools became worn out after 255 s which is considerable compared to carbide tools. Also, the finished surface caused by cemented carbide CP500 indicated the worst quality.

Metal matrix composites (MMC) introduced special features such as resistance to wear and high strength to weight ratio and these characteristics categorized them as difficult-to-cut materials in the field of machining. In the current paper, a novel study on the cutting fluid emulsion 5% role in the machinability of a magnesium-based metal matrix composite reinforced by silicon carbide (SiC) particles is presented. AZ91 magnesium alloy, with nominal composition Mg-9Al-1Zn, composites were made using stir casting method. Then, the composite samples were machined and the cutting parameters such as cutting speed, feed rate and side cutting edge angle were varied to assess their effects on the wear and surface roughness. To measure and analyze the wear, optical and scanning electron microscope (SEM) were used. Also, elemental analysis through energy-dispersive X-ray spectroscopy (EDS) was accomplished. Surface roughness of machined samples were measured by a profilometer and 3D surface topography. Results of SEM and EDS images indicated that SiC particles included in the composites act as grinders and remove the surface of tool even in a short time because of the severe abrasion. Additionally, surface of machined MMCs contains some defects such as cracks, broken SiC, and unwanted deformations. Using cutting fluid emulsion 5% enhanced the tool life as well as the surface quality remarkably for different cutting speeds, feed rates and cutting edge angles although finished surface of the samples were oxidized. Also, the cutting fluid considerably reduced the amount of adhered materials on the flank face.