Electronic Theses and Dissertations

Identifier

6432

Author

Jingzhe Zhang

Date

2019

Date of Award

4-30-2019

Document Type

Thesis

Degree Name

Master of Science

Major

Mechanical Engineering

Committee Chair

Ali Fatemi

Committee Member

Gladius Lewis

Committee Member

Steve Wayne

Abstract

Additive manufacturing (AM) has become a very popular topic recently due to its many advantages including short build cycles, convenience of customozation, and most importantly the ability to build components with complex geometry. However, the surface condition of additive manufactured components is not always satisfactory, particularly with respect to fatigue performance. This is because the as-built surface tends to be rough and post surface treatments or processes such as machining and polishing may not be applicable to all AM parts. On the other hand, since many components are under cyclic loading consisting of normal and shear stress, multiaxial fatigue behavior is one of the most important aspects to evaluate. This paper evaluates the surface roughness effect on fatigue behaviors of Ti-6Al-4V allloy samples additively manufactured by laser based powder bed fusion method (L-PBF). Fully reversed axial, torsional, and combined axial-torsion fatigue tests were conducted on specimens with different surface conditions and with different post heat treatments (annealed and HIP). Fatigue life predictions were made using linear elastic fracture mechanic with satisfactory results, as compared to experimental results.

Comments

Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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