Development of Bio-Compatible Metallic Structures Using Direct Metal Deposition Process

2012 ◽  
Vol 576 ◽  
pp. 141-145
Author(s):  
Syed H. Riza ◽  
Syed H. Masood ◽  
Cui'e Wen ◽  
William Song
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Laser Power ◽  
Deposition Process ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Metal Powders ◽  
Micro Hardness ◽  
Metallic Structures ◽  
Ti6al4v Titanium Alloy

This paper investigates the capabilities of Direct Metal Deposition (DMD) process, which is a novel additive manufacturing technique, for creating structures that can be used as bone implants. Emphasis is on the use of bio-compatible metals, because metals are the most suitable materials in terms of mechanical strength when the requirement arises for supporting and replacing the load bearing bones and joints such as hip and knee. Specimens using two different metal powders, 41C stainless steel and Ti6Al4V titanium alloy, are generated by DMD process on mild steel and titanium plates as substrates respectively. Metallographic samples were made from the cladding, and tested for surface roughness and micro-hardness. The results indicate that at low laser power, hard and strong structures with good porosity can be successfully created using the DMD system.

An Experimental Characterization of Powder/Substrate Interaction during Direct Metal Deposition for Additive Manufacturing

2019 ◽  
Vol 813 ◽  
pp. 435-440
Author(s):  
Maurizio Troiano ◽  
Alessia Teresa Silvestri ◽  
Fabio Scherillo ◽  
Andrea El Hassanin ◽  
Roberto Solimene ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Surface Morphology ◽  
Laser Power ◽  
Surface Characterization ◽  
Spot Size ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Metal Powders ◽  
Substrate Interaction

The physical behavior of metal powders during laser-based additive manufacturing processes has been investigated. In particular, an experimental campaign of direct metal deposition has been carried out to evaluate the effect of the laser power and spot size on the powder/substrate interaction and on the surface morphology of the final piece. A fast-camera has been used to evaluate the interaction phenomena during the printing process, while confocal microscopy has been carried out to measure the surface morphology of the samples. Results highlighted that increasing the laser power and laser spot size, the particle impact velocity is about constant, while the powder/laser/substrate interaction zone increases. As a consequence, the mean thickness increases, as confirmed by surface characterization.

Mechanical performance of plymetal structures subjected to impact loading

2017 ◽  
Vol 9 (1) ◽  
pp. 65-76
Author(s):  
SH Masood ◽  
D Ruan ◽  
P Rajapatruni
Keyword(s):  
Stainless Steel ◽  
Mechanical Performance ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Layer By Layer ◽  
Metal Powders ◽  
Metallic Structure ◽  
Stainless Steel 316L ◽  
Ballistic Performance ◽  
Ballistic Resistance

Plymetal is a new type of composite metallic structure based on the concept of plywood created by laser direct metal deposition additive manufacturing technology. Two different metal powders, 316L stainless steel and H13 tool steel, are deposited in alternative parallel rows in each layer in the defined orientations to create a plymetal structure. In this research, the plymetal was manufactured by the POM DMD 505 machine, in which a laser beam melts various metal powders deposited through a coaxial nozzle in a layer-by-layer manner to form a metallic structure. The ballistic performance of plymetal structures was then experimentally studied for high impact applications. Ballistic tests were carried out using a high-pressure gas gun. The plymetal plates of 3-mm-thick were subjected to impact of projectiles at various velocities and the results were compared with test results of stainless steel plates of different thicknesses. Results show that the ballistic resistance of the direct metal deposition generated plymetal structure is better than the ballistic resistance of the stainless steel 316L with the same thickness. Vickers hardness and face deformation characteristics of the plymetal samples and stainless steel samples were also investigated.

Study of Ultrasonic Vibration Laser Metal Deposition Process

2012 ◽  
Author(s):  
Xueyong Chen ◽  
Todd Sparks ◽  
Jianzhong Ruan ◽  
Frank Liou
Keyword(s):  
Stainless Steel ◽  
Ultrasonic Vibration ◽  
316L Stainless Steel ◽  
Steel Powder ◽  
Deposition Process ◽  
Metal Deposition ◽  
Laser Deposition ◽  
Laser Metal Deposition ◽  
Micro Hardness ◽  
Laser Direct Deposition

This paper presents the usage of ultrasonic vibration in laser direct deposition of 316L (stainless steel) powder. Ultrasonic vibration is used to refine the crystalline structure of the deposition. The ultrasonic vibration device vibrates in the laser deposition system along the Z axis while the system is performing metal deposition. A design of experiments approach is applied in studying the effect of vibration on the deposited material. Vibration during deposition led to grain refinement and an increase in micro-hardness. Also, vibration frequency is a significant factor in determining microstructure.

A Study of Microstructure and Surface Hardness of Parts Fabricated by Laser Direct Metal Deposition Process

2010 ◽  
Vol 129-131 ◽  
pp. 648-651 ◽  
Author(s):  
Mehdi Soodi ◽  
Milan Brandt ◽  
Syed H. Masood
Keyword(s):  
Stainless Steel ◽  
Tool Steel ◽  
316L Stainless Steel ◽  
Surface Hardness ◽  
Deposition Process ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Significant Difference ◽  
Aluminium Bronze ◽  
Hardness Values

This paper presents an investigation on the microstructure and surface hardness of the parts fabricated by laser assisted Direct Metal Deposition (DMD) technology. A series of engineering metallic alloy powders were used in the DMD process to produce simple 3D geometric structures. The alloy powders investigated include: 316L stainless steel, 420 Stainless Steel, Stellite(R) 6, tool steel (H13), Cholmoloy (Ni Based alloy), and Aluminium Bronze. These were chosen due to their frequent application in engineering parts and components. The microstructure and hardness values have been compared to those of the wrought products (as annealed) as reported in the SAE standards, Heat treater’s guide to metals ASM international, and material data sheets supplied by the materials manufacturers. A significant difference is reported in both hardness and microstructure of the laser deposited samples compared to those of the wrought form.

Experimental and Numerical Analysis of the Powder Flow in a Multi-Channel Coaxial Nozzle of a Direct Metal Deposition System

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Piyush Pant ◽  
Dipankar Chatterjee ◽  
Sudip Kumar Samanta ◽  
Aditya Kumar Lohar
Keyword(s):  
Gas Flow ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Deposition Process ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Powder Flow ◽  
Coaxial Nozzle ◽  
Proposed Model ◽  
Blown Powder

Abstract The work explores the powder transport process, using numerical simulation to address the dynamics of the powder flow in an in-house built multi-channel coaxial nozzle of a direct metal deposition (DMD) system. The fluid turbulence is handled by the standard k–ɛ and k–ω turbulence models, and the results are compared in order to predict their suitability. An image-based technique using CMOS camera is adopted to determine the powder flow characteristics. The model is validated with the in-house experimental results and verified available results in the literature. The findings of this work confirms the application of the k–ω model for powder gas flow investigations in blown powder additive manufacturing (AM) processes due to its better predictive capability. The proposed model will assist in simulating the direct metal deposition process.

Surface Hardening of AISI 420 Stainless Steel by Using a Nanosecond Pulse Laser

2018 ◽  
Vol 911 ◽  
pp. 44-48 ◽  
Author(s):  
Ornsurang Netprasert ◽  
Viboon Tangwarodomnukun ◽  
Chaiya Dumkum
Keyword(s):  
Stainless Steel ◽  
Pulse Laser ◽  
Laser Power ◽  
Nanosecond Pulse ◽  
Laser Hardening ◽  
Micro Hardness ◽  
Hardening Process ◽  
Aisi 420 ◽  
Scan Speed ◽  
Nanosecond Pulse Laser

Unlike the conventional heat treatments, laser hardening process can selectively and locally harden the workpiece surface with minimum part distortion, thus making the process suitable for small or thin workpieces. To elucidate a better understanding of process performance, this paper presents an investigation of laser hardening process for AISI 420 martensitic stainless steel. A nanosecond pulse laser was used as a heat source to harden the metal surface. The effects of laser power scan overlap and scan speed on micro-hardness and case depth were experimentally examined. The results revealed that the micro-hardness of stainless steel surface increased from 242 HV to 1700 HV without any sign of surface melting. The depth of hardened layer was found to be 60-80 µm depending on laser power, scan speed and scan overlap applied. In addition, the scan overlap of 50% was recommended to lessen the deviation of micro-hardness across the laser-scanned area.

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