Date of Award
M.S. in Engineering Science
Arunachalam M. Rajendran
University of Mississippi
There has been rapidly growing interest in the sintering process of nanoparticles (NPs) among academia and modern industry due to their promising applications in additive manufacturing (AM) based on the overall improved properties at nanoscale. In the past decade a lot of experimental and computational work has been conducted to study the sintering process of powder materials. However there is still a significant knowledge gap in a fundamental understanding of the thermodynamics and nanostructural evolution of NPs undergoing additive manufacturing. This thesis aims to gain fundamental insights into melting behavior of different materials including single-crystal bimetallic core/shell alloy and intermetallic alloy NPs. (Molecular dynamics) MD simulations were used to mimic selective laser melting (SLM) process during AM. Through a series of simulations involving two-NP systems with varying core-volume fractions it is revealed that there is a significant effect associated with the interfacial melting of the core metal and gradual alloying of the molten aluminum (Al) shell during a two-stage melting process in a “melting zone.” In the following parts of the thesis further investigation on deformation mechanism on the produced single-crystal titanium (Ti) and bimetallic Ti/Al alloy five-NP-chain systems under high strain rate is conducted to gain the tensile properties of the materials. It is found that the heating rate final heating temperature and core-volume fraction of NPs have strong effects on the tensile properties of the final product. Through detailed investigation on deformation mechanisms on the tensile properties of the products at high strain rate formation of stacking faults and icosahedral structures are identified through comneighbor analysis. This study of different materials at nanoscale will shed light on sintering process and prototyping in AM.
Jeon, Jungmin, "Molecular dynamics study of sintering behavior of single-crystal, bimetallic core/shell alloy, and intermetallic alloy nanoparticles" (2019). Electronic Theses and Dissertations. 1767.