Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 7 of 7
Full-Text Articles in Mechanical Engineering
Remanufacturing Of Precision Metal Components Using Additive Manufacturing Technology, Xinchang Zhang
Remanufacturing Of Precision Metal Components Using Additive Manufacturing Technology, Xinchang Zhang
Doctoral Dissertations
"Critical metallic components such as jet engine turbine blades and casting die/mold may be damaged after servicing for a period at harsh working environments such as elevated temperature and pressure, impact with foreign objects, wear, corrosion, and fatigue. Additive manufacturing has a promising application for the refurbishment of such high-costly parts by depositing materials at the damaged zone to restore the nominal geometry. However, several issues such as pre-processing of worn parts to assure the repairability, reconstructing the repair volume to generate a repair tool path for material deposition, and inspection of repaired parts are challenging. The current research aims …
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
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 Optimizing Particle Size In Laser Metal Deposition With Blown Pre-Mixed Powders, Wei Li, Jingwei Zhang, Xinchang Zhang, Sreekar Karnati, Frank W. Liou
Effect Of Optimizing Particle Size In Laser Metal Deposition With Blown Pre-Mixed Powders, Wei Li, Jingwei Zhang, Xinchang Zhang, Sreekar Karnati, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Functionally Graded Material (FGM) is often fabricated by Laser metal deposition with pre-mixed multiple powders (PMM-powder). Since the supplied PMM-powder directly affects FGM’s composition, investigation on PMM-powder’s property is greatly needed. This paper employed experimental method to observe an important problem: PMM-powder separation in fabricating FGM. A novel particle size optimization method was introduced as solution to eliminate the powder separation. Pre-mixed pure Cu and 4047 Al powders were used to do two experiments. The first experiment result disclosed the existence of powder separation. By optimizing the particle size, the PMM-powder separation was effectively solved in the second experiment result.
Defects Classification Of Laser Metal Deposition Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou
Defects Classification Of Laser Metal Deposition Using Acoustic Emission Sensor, Haythem Gaja, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser metal deposition (LMD) is an advanced additive manufacturing (AM) process used to build or repair metal parts layer by layer for a range of different applications. Any presence of deposition defects in the part produced causes change in the mechanical properties and might cause failure to the part. In this work, defects monitoring system was proposed to detect and classify defects in real time using an acoustic emission (AE) sensor and an unsupervised pattern recognition analysis. Time domain and frequency domain, and relevant descriptors were used in the classification process to improve the characterization and the discrimination of the …
Ti-Fe Intermetallics Analysis And Control In Joining Titanium Alloy And Stainless Steel By Laser Metal Deposition, Wei Li
Masters Theses
"Direct fusion joining titanium alloy and stainless steel can cause brittle Ti-Fe intermetallics which compromise the mechanical properties of diffusion bonds between titanium alloys and stainless steel. Therefore, filler metals are required as transition layers. In this research, stainless steel metallic powder was directly deposited on the titanium alloy substrate by laser beam, the Ti-Fe intermetallic phases formed in this process were investigated through analyzing fracture morphology, phase identification, and Vickers Hardness Number (VHN). After that, Laser Metal Deposition (LMD) was applied to explore a new fabricating process to join Ti6Al4V and SS316. A transition composition route was introducedTi6Al4V → …
A Smooth Toolpath Generation Method For Laser Metal Deposition, Renwei Liu, Zhiyuan Wang, Yunlu Zhang, Todd E. Sparks, Frank W. Liou
A Smooth Toolpath Generation Method For Laser Metal Deposition, Renwei Liu, Zhiyuan Wang, Yunlu Zhang, Todd E. Sparks, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser metal deposition (LMD), also known as direct metal deposition (DMD) or laser engineered net shaping (LENS), which uses a laser beam to form a melt pool on a metallic substrate, into which powder or wire is fed. The conventional contour and zigzag toolpath pattern for LMD are discontinuous at turn points or corner points. The discontinuous toolpath causes uneven deposition, which brings height variation and porosity problems. This paper aims to develop a smooth toolpath generation method for LMD to improve the deposition quality. A parametric curve equation based on trigonometric functions is derived and built. It can be …
Dc-Gain Layer-To-Layer Stability Criterion In Laser Metal Deposition Processes, Patrick M. Sammons, Douglas A. Bristow, Robert G. Landers
Dc-Gain Layer-To-Layer Stability Criterion In Laser Metal Deposition Processes, Patrick M. Sammons, Douglas A. Bristow, Robert G. Landers
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In Laser Metal Deposition (LMD), a blown powder metal additive manufacturing process, functional metal parts are fabricated in a layer-by-layer fashion. In addition to the in-layer dynamics, which describe how the process evolves within a given layer, the additive-fabrication property of LMD creates a second set of dynamics which describe how the process evolves from layer-to-layer. While these dynamics, termed layer-to-layer dynamics, are coupled with both the in-layer dynamics and the process operating conditions, they are not widely considered in the modeling, process planning, or process control of LMD operations. Because of this, seemingly valid choices for process parameters can …