Date of Award
Summer 2019
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Mechanical Engineering
First Advisor
Rice, James
Second Advisor
Kim, Kyuil
Third Advisor
Domblesky, Joseph
Abstract
Mapping of local density fractions and a mathematically approximated density fraction model of sintered powder metal were studied in this research. Specimens were studied utilizing an image analysis software, HCImage, and local density fraction maps were acquired for each sintering condition. A regression function of sintering temperature, sintering time, radius and depth was then derived from the local density fractions. The experimental procedures including specimen preparation, image analysis, and data analysis are demonstrated in detail within this research. Through the local density maps and the regression function, two objectives were sought as follow:1. Determination of the density fraction gradient that is closely related to mechanical properties such as strength and hardness.2. Prediction of the density fraction by sintering temperature and sintering time from the regression function. The first objective pertained to the relationship between theoretical approach and experimental result. A specific theoretical approach including derivation, initial and boundary conditions as well as contouring a density fraction gradient map is detailed. The gradient map of specimens for each sintering condition were investigated via an optical method as well. The relationship between the theoretical and the optical methods was examined. Continuing with the prediction that can be used to estimate the density fraction in a specific sintering condition, linear regression methods for second order functions were developed.