Showing 2 results for Abrinia
M. Hoghooghi, O. Jafari, S. Amani, G. Faraji, K. Abrinia,
Volume 16, Issue 4 (December 2019)
Abstract
Spread extrusion is a capable method to produce different samples with a wider cross-section from the smaller billets in a single processing pass. In this study, dish-shaped samples are successfully produced from the as-cast cylindrical AM60 magnesium alloy at 300 °C, the mechanical properties and microstructural changes of the final specimens are precisely evaluated. Due to the high amount of plastic strain, which is applied to the initial billet during the material flow in the expansion process, grain refinement occurred as a result of recrystallization and subsequently good mechanical properties achieved. Therefore, mean grain size reduced from 160 µm to 14 µm and initial equiaxed grains changed to the elongated ones surrounded by fine grains. Also, microhardness measurements indicate that hardness increased from 51 Hv to 70 Hv. Some fluctuations were also observed in the hardness profile of the sample which was mainly related to the bimodal structure of the final microstructure. Good mechanical properties, fine microstructure, and also the ability to produce samples with higher cross-section make the spread extrusion process a promising type of extrusion.
Yaser Vahidshad, Karen Abrinia,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
Selective laser melting (SLM) is a widely used additive manufacturing method for 3D-printing metal parts. This study investigates how SLM parameters affect the density, microstructure, and mechanical properties of maraging steel 300. A process window was developed, revealing that maximum density and minimal porosity are achieved when laser energy density exceeds 50 J/mm³. Optimal parameters—100 mm/s scan speed, 20 μm layer thickness, 0.15 mm hatch distance, Stripe scanning strategy, and XZ build direction—were identified. Optimal processing reduced porosity, increased martensite content, and enhanced strength, reaching 1064 MPa and improving by 75% to 1862 MPa after aging and solution treatment. Strength gains were attributed to the uniform dispersion of nano-sized precipitates (such as Ni(Mo)3 and Ni(Ti, Al)3) within the martensitic matrix. Additionally, it was found that higher cooling rates further improve the mechanical strength of heat-treated parts.
