scholarly journals Experimental and Numerical Investigation in Directed Energy Deposition for Component Repair

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1409
Author(s):  
Lan Li ◽  
Xinchang Zhang ◽  
Frank Liou
Keyword(s):  
Mechanical Properties ◽  
Energy Deposition ◽  
Surface Defects ◽  
Repair Process ◽  
Field Analysis ◽  
Element Analysis ◽  
Mechanical Field ◽  
Directed Energy Deposition ◽  
Considerable Impact ◽  
Directed Energy

Directed energy deposition (DED) has been widely used for component repair. In the repair process, the surface defects are machined to a groove or slot and then refilled. The sidewall inclination angle of the groove geometry has been recognized to have a considerable impact on the mechanical properties of repaired parts. The objective of this work was to investigate the feasibility of repairing various V-shaped defects with both experiments and modeling. At first, the repair volume was defined by scanning the defective zone. Then, the repair volume was sliced to generate the repair toolpath. After that, the DED process was used to deposit Ti6Al4V powder on the damaged plates with two different slot geometries. Mechanical properties of the repaired parts were evaluated by microstructure analysis and tensile test. Testing of the repaired parts showed excellent bonding between the deposits and base materials with the triangular slot repair. 3D finite element analysis (FEA) models based on sequentially coupled thermo-mechanical field analysis were developed to simulate the corresponding repair process. Thermal histories of the substrate on the repair sample were measured to calibrate the 3D coupled thermo-mechanical model. The temperature measurements showed very good verification with the predicted temperature results. After that, the validated model was used to predict the residual stresses and distortions in the parts. Predicted deformation and stress results can guide the evaluation of the repair quality.

Repairing Automotive Dies With Directed Energy Deposition: Industrial Application and Life Cycle Analysis

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Jennifer Bennett ◽  
Daniel Garcia ◽  
Marie Kendrick ◽  
Travis Hartman ◽  
Gregory Hyatt ◽  
...  
Keyword(s):  
Life Cycle ◽  
Environmental Impacts ◽  
Energy Deposition ◽  
Repair Process ◽  
Directed Energy Deposition ◽  
Die Life ◽  
Hybrid Repair ◽  
Directed Energy ◽  
Number Of Cycles ◽  
Manufacturing Technologies

Powder-based additive manufacturing technologies are developing rapidly. To assess their applicability, comparison of performance and environmental impacts between additive technologies and conventional techniques must be performed. Toyota manufactures over two million aluminum four-cylinder engines in the U.S. each year via die casting. The dies used in this process are traditionally repaired via tungsten inert gas (TIG) welding and only last an average of 20.8% of the number of cycles of the original die life before another repair is needed. A hybrid repair process involving machining away the damaged areas and then rebuilding them additively via powder-blown directed energy deposition (DED) has been developed. The die repaired via DED resulted in the same life as the original die. The use of DED repair eliminated the need for emergency repairs and nonscheduled downtime on the line because the DED repaired dies last for as many cycles as the original die before another repair is needed. Life cycle analyses were conducted comparing the traditional welding repair process to the DED repair process. The results show that the DED repair process results in significantly less damage to the assessed impact categories except for ionizing radiation. Therefore, it can be concluded that the DED repair process could lessen most environmental impacts compared to traditional welding repair. Further work toward increasing energy and material efficiencies of the method could yield further reductions in environmental impacts.

scholarly journals Mechanical Properties of Tool Steels with High Wear Resistance via Directed Energy Deposition

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 282 ◽  
Author(s):  
Gyeong Yun Baek ◽  
Gwang Yong Shin ◽  
Ki Yong Lee ◽  
Do Sik Shim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Energy Deposition ◽  
High Wear Resistance ◽  
Matrix Microstructure ◽  
Microstructure Observation ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Post Deposition

This study focused on the mechanical and metallurgical characteristics of high-wear-resistance steel (HWS) deposited using directed energy deposition (DED) for metal substrate hardfacing or repairing. As post-deposition heat treatment changes the metallurgical characteristics of deposits, the effect of post-deposition heat treatment on the mechanical properties was investigated via microstructure observation and by conducting hardness, wear, and impact tests. The obtained micro-images showed that the deposited HWS layers exhibit cellular and columnar dendrites, and the microstructure of heat-treated HWS (HT-HWS) transformed its phase during quenching and tempering. The hardness and wear resistance of the HT-HWS deposits were higher than those of the HWS deposited specimen, whereas the latter exhibited a higher fracture toughness. The matrix microstructure and carbide characteristics, which are characterized by the chemical composition of the materials, significantly influenced the mechanical properties.

Sign in / Sign up

Export Citation Format

Share Document