Date of Award

8-16-2024

Document Type

Open Access Thesis

Department

Mechanical Engineering

First Advisor

Caizhi Zhou

Abstract

Additive manufacturing (AM) has emerged as a promising technique in the manufacturing industry for producing complex metal components as it provides shape freedom and simplistic processing chain.

Powder bed fusion is the widely used AM technique that uses laser or electron beam as the energy source to melt the metal powder and deposit it in a layer-by-layer fashion. While doing so, the previously molten layers are constantly are in re-heating and re-cooling processes which end up creating an intricate solidification for the deposited layers. Due to the complexity involved in the thermal cycles for the solidification process, columnar grains develop. These kind of columnar grain structures are in network and quite common in the additively manufactured metallic materials. These cellular structures have a cell wall with high dislocation density and a cell interior with a dislocation density lower than the cell wall which makes the microstructure heterogeneous. Heterogeneous microstructures can be both beneficial for increasing the strength and have a detrimental effect to the ductility.

Therefore, a nonlocal crystal plasticity finite element method (CPFEM) is employed as a numerical method to study these heterogeneous microstructures for better understanding and controlling the heterogeneity. Several representative volume elements (RVEs) comprising of FCC lattice with brick elements is created to analyze the mechanical behavior of these microstructures.

Rights

© 2024, Md Mahabubur Rohoman

Download

Share

COinS