Award Date

12-1-2015

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Committee Member

Brendan O’Toole

Second Committee Member

Mohamed Trabia

Third Committee Member

Samaan Ladkany

Fourth Committee Member

Zhiyong Wang

Fifth Committee Member

Moses Karakouzian

Number of Pages

258

Abstract

The effect of hypervelocity projectile impact on the crystalline grain structure near the target impact location of A36 steel has been studied. A36 steel is a mostly single phase body centered cubic material (BCC). Impact velocities ranged from 3.54 to 6.70 km/sec. Target materials were studied before and after impact to determine if these impact conditions result in a phase change of the A36. Scanning electron microscopy, electron back-scatter diffraction, and x-ray diffraction methods were used to investigate deformation, lattice defects, twinning, and phase transformation. A limited number of impacted targets made from 304L and HY100 steels were also examined. These alloys contain the BCC crystalline phase along with face centered cubic (FCC) and hexagonal closed pack (HCP) structures. Grain size near impact is compacted near impact site. Also twinning was present closer to the impact area, and gradually dissipated away further from the impact zone. While increasing impact momentum increased the HCP percentage.

Keywords

304L Steel; A36 Steel; EBSD microscope; HY100 Steel; Impact; Microscopy

Disciplines

Engineering | Engineering Science and Materials | Materials Science and Engineering

Language

English


Share

COinS