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Full-Text Articles in Engineering

On The Feasibility Of Tailoring Copper-Nickel Functionally Graded Materials Fabricated Through Laser Metal Deposition, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk Mar 2019

On The Feasibility Of Tailoring Copper-Nickel Functionally Graded Materials Fabricated Through Laser Metal Deposition, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this study, pulse‐width modulation of laser power was identified as a feasible means for varying the chemical gradient in copper—nickel‐graded materials. Graded material deposits of 70 wt. %. copper‐30 wt. %. nickel on 100 wt. %. nickel and vice versa were deposited and characterized. The 70/30 copper—nickel weight ratio in the feedstock powder was achieved through blending elemental copper and 96 wt. %. Ni—Delero‐22 alloy. At the dissimilar material interface over the course of four layers, the duty cycle of power was ramped down from a high value to optimized deposition conditions. This change was theorized to influence the …


Design And Fabrication Of Functionally Graded Material From Ti To Γ-Tial By Laser Metal Deposition, Xueyang Chen, Lei Yan, Joseph William Newkirk, Frank W. Liou Aug 2017

Design And Fabrication Of Functionally Graded Material From Ti To Γ-Tial By Laser Metal Deposition, Xueyang Chen, Lei Yan, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

Functionally graded material (FGM) is one kind of advanced material characterized by a gradual change in properties as the position varies. The spatial variation of compositional and microstructure over volume is aimed to control corresponding functional properties. In this research, when 100% γ-TiAl was directly deposited on pure Ti substrate, cracks were formed within the γ-TiAl layer. Then a six-layer crack-free functionally graded material of Ti/TiAl was designed and fabricated by laser metal deposition (LMD) method, with composition changing from pure Ti on one side to 100% γ-TiAl on the other side. The fabricated FGM was characterized for material properties …


Effect Of Powder Particle Size On The Fabrication Of Ti-6al-4v Using Laser Metal Deposition From Elemental Powder Mixture, Xueyang Chen, Lei Yan, Wei Li, Frank W. Liou, Joseph William Newkirk Jan 2016

Effect Of Powder Particle Size On The Fabrication Of Ti-6al-4v Using Laser Metal Deposition From Elemental Powder Mixture, Xueyang Chen, Lei Yan, Wei Li, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct LMD (laser metal deposition) was used to fabricate thin-wall Ti-6Al-4V using the powder mixture of Ti-6 wt.%Al-4 wt.%V. SEM (scanning electron microscopy), OM (optical microscopy) and EDS (energy dispersive spectroscopy) were employed to examine the chemical composition and microstructure of the as-deposited sections. Vickers hardness tests were then applied to characterize the mechanical properties of the deposit samples which were fabricated using pre-mixed elemental powders. The EDS line scans indicated that the chemical composition of the samples was homogenous across the deposit. After significant analysis, some differences were observed among two sets of deposit samples which varied in the …