عنوان

Wire + Arc Additive Manufacturing of High-Performance Alloys

TL52028

انگلیسی

Wire + Arc Additive Manufacturing of High-Performance Alloys

[Thesis]

Tanvir, Ali Newaz Mohammad

Kim, Duckbong

Tennessee Technological University

2019

110 p.

M.S.

Tennessee Technological University

2019

The innovation of metal additive manufacturing (AM) techniques is sought to replace the existing manufacturing processes (i.e., casting, forming, and subtractive manufacturing) by offering several benefits in terms of cost and process simplicity. The wire + arc additive manufacturing (WAAM) is a popular addition of metal AM processes due to its ability to build defect-free large-sized parts with a high deposition rate and better energy efficiency. Due to these benefits, AM researchers are working hard towards the development of this process to be used in manufacturing industries. The WAAM requires minor attention in development of system setup, due to the advantages of using conventional welding systems. In addition, the conventional welding processes hold verified guidelines for welding of wide varieties of metal. However, the WAAM needs stacking of metal in a layer by layer fashion, rather than depositing a single pass metal like conventional welding. Thus, the final properties (i.e., microstructure and mechanical properties) of metal parts fabricated by WAAM, can be quite different than the conventional welded parts. Towards that difference, WAAM researchers are currently focusing more on establishing a relationship between the WAAM process and the manufactured part properties. This study is an effort to establish the guideline of WAAM for two high-performance materials, such as Inconel 625 and H13 tool steel. Two different geometrical shapes were fabricated with these materials relating to their applications in industries. A cold metal transfer-based gas metal arc welding system is used as the manufacturing process. The microstructure and mechanical properties for both the materials are analyzed and correlated with the process. The as-manufactured Inconel 625 seems to have lower tensile strength while compared with other AM processes found in the literature. Precipitation of Laves phases is found responsible for the low strength. A heat-treatment procedure was successfully employed to improve the mechanical properties by removing the Laves phase. The heat-treatment also helped to precipitate MC carbide and delta phases that also assisted in improving mechanical properties. The as-manufactured H13 tool steel has shown comparable mechanical strength with the other AM processes found in the literature. However, this study evaluates the microstructural stability and mechanical performance of H13 at high-temperature, such as at 300 °C and 600 °C, due to the frequent use of this material at these conditions. The microstructure remained stable as verified by the in-situ x-ray diffraction. The room and high-temperature mechanical properties are also comparable to the other AM processes found in the literature. The result of the in-depth microstructural study, the mechanical property evaluation and comparison, and the successful heat-treatment procedure have provided a high prospect of these two investigated materials to be used in the WAAM industry. This study can be highly significant in preparing a process-property guideline for the wire + arc additive manufacturing of Inconel 625 and H13 tool steel.

High temperature physics

Materials science

Mechanical engineering

Mechanics

Tanvir, Ali Newaz Mohammad

Kim, Duckbong

Tennessee Technological University

p

[Thesis]

276903

a

Y