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Effect of boron additions on microstructure and mechanical properties of titanium alloys produced by the armstrong process

Blank, Jonathan P
http://rave.ohiolink.edu/etdc/view?acc_num=osu1198718818

Abstract Details

2008, Doctor of Philosophy, Ohio State University, Materials Science and Engineering.
The beneficial influence of boron additions on processing, microstructure, physical and mechanical properties of various titanium alloys has been recognized since 1950’s. However, boron additions to titanium alloys to obtain specific microstructures and mechanical properties for several niche applications, including automotive and aerospace, have been actively studied during the past 25 years. The addition of boron concentrations greater than 0.05 wt.% to titanium alloys creates a dispersion of TiB. The presence of TiB enhances the tensile and fatigue strengths as well as the wear resistance as compared to the original titanium alloy. Although these improvements in mechanical properties are attractive, there are still two major obstacles in using these alloys: (1) relationship of microstructure and mechanical properties in Ti-B alloys needs further investigation to optimize the alloys for specific commercial applications; and (2) cost to benefit ratio of producing these alloys is high for a given application(s). The Armstrong process is a novel process that can produce commercially pure (CP) titanium and titanium alloy powder directly from TiCl4 (and other metal halides or as required, to obtain the desired alloy composition). The Armstrong process uses sodium as a reducing agent, with similar reactions as the Hunter process using sodium as a reducing agent and Kroll process using magnesium as a reducing agent. The Armstrong process forms CP-Ti and titanium alloyed powder, which can be directly consolidated or melted into the final product. In comparing the downstream processing steps required by the Kroll and Hunter processes with direct consolidation of Armstrong powder, several processing features or steps are eliminated: (1) restriction of batch processing of material, (2) blending of titanium sponge and master alloy material to create titanium alloys, (3) crushing of the sponge product, (4) melting, and (5) several handling steps. The main objective of this research was to characterize structure and properties of CP-Ti and Ti-B alloys produced by the Armstrong process. Particular emphasis has been placed on improved understanding of the strengthening mechanisms associated with the addition of boron to titanium alloys.
James Williams (Advisor)
249 p.
Textile Technology
Titanium; Titanium-boron; TiB; Commercially Pure Titanium; CP-Ti; Titanium microstructure; Titanium-boron microstructure; Tensile; Notched Fatigue; Fatigue Crack Growth

Recommended Citations

Citations

  • Blank, J. P. (2008). Effect of boron additions on microstructure and mechanical properties of titanium alloys produced by the armstrong process [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1198718818

    APA Style (7th edition)

  • Blank, Jonathan. Effect of boron additions on microstructure and mechanical properties of titanium alloys produced by the armstrong process. 2008. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1198718818.

    MLA Style (8th edition)

  • Blank, Jonathan. "Effect of boron additions on microstructure and mechanical properties of titanium alloys produced by the armstrong process." Doctoral dissertation, Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1198718818

    Chicago Manual of Style (17th edition)

osu1198718818
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This open access ETD is published by The Ohio State University and OhioLINK.