Award Date

May 2016

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

Brendan J. O'Toole

Second Committee Member

Mohamed Trabia

Third Committee Member

Zhiyong Wang

Fourth Committee Member

Robert Schill

Number of Pages

249

Abstract

The objective of this research topic is to determine mechanical properties of Alloy EP-823 and to provide a mechanistic understanding of its sensitivity to both thermal treatment and performance temperature. EP-823 is a leading target material for accelerator-driven waste transmutation applications. Overall, the tensile test results of Alloy EP-823 indicated a general trend of decreasing mechanical performance with an increase in tempering time. An increase in tempering time had a statistically significant inverse relationship with ultimate tensile strength (UTS) and yield strength (YS). An increase in tempering time did not have a significant effect on elongation and reduction in area. Performance temperature effects, however, were more noticeable, trending UTS and YS values downward with increasing temperature. Elongation values experience a slight reduction up to 300°C then ramped upwards for increasing temperatures. Reduction of area values appeared unaffected by an increase in temperature up to 400°C but did experience an increase with greater temperatures beyond 400°C. With increasing temperature the mechanical properties changed gradually and predictably up to 400°C, but at 500°C they changed drastically, implying that a critical temperature can be found between 400°C and 500°C. This temperature could be important to design integrity. At performance temperatures beyond this critical temperature the material experiences unstable deformation shortly after reaching the yield strength value, exhibiting severely truncated uniform plastic deformation characteristics.

Keywords

EP-823; ferritic-martensitic; heat treatment; high temperature; target material; tensile properties

Disciplines

Engineering Science and Materials | Materials Science and Engineering | Mechanical Engineering

Language

English


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