Effect of Friction-stir Processing on the Wear Behavior of Titanium (Ti-1Al-8V-5Fe) and Stainless Steel (A-286) Alloys

PDF Version Also Available for Download.

Description

The effect of friction stir processing (FSP) on the mechanical wear behavior was investigated for Ti-1Al-8V-5Fe (Ti-185) and stainless steel (Incoloy® A-286) alloys. The Ti-185 and A-286 alloys were tested in different processing conditions, including as rolled (AR), AR+FSP, and AR+FSP+aged. A high frequency reciprocating rig was used to simulate fretting-type wear of these alloys at room temperature. The Vickers micro-hardness and wear rates were calculated and compared for each processing condition. It was determined that along with increasing hardness in the stir zones, FSP resulted in improved wear resistance for both alloys. Specifically, wear rates in the stir zones ... continued below

Physical Description

viii, 39 pages : illustrations (chiefly color)

Creation Information

Tinubu, Olusegun Olukunle May 2015.

Context

This thesis is part of the collection entitled: UNT Theses and Dissertations and was provided by UNT Libraries to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 249 times . More information about this thesis can be viewed below.

Who

People and organizations associated with either the creation of this thesis or its content.

Chair

Committee Members

Publisher

Rights Holder

For guidance see Citations, Rights, Re-Use.

  • Tinubu, Olusegun Olukunle

Provided By

UNT Libraries

With locations on the Denton campus of the University of North Texas and one in Dallas, UNT Libraries serves the school and the community by providing access to physical and online collections; The Portal to Texas History and UNT Digital Libraries; academic research, and much, much more.

Contact Us

What

Descriptive information to help identify this thesis. Follow the links below to find similar items on the Digital Library.

Degree Information

Description

The effect of friction stir processing (FSP) on the mechanical wear behavior was investigated for Ti-1Al-8V-5Fe (Ti-185) and stainless steel (Incoloy® A-286) alloys. The Ti-185 and A-286 alloys were tested in different processing conditions, including as rolled (AR), AR+FSP, and AR+FSP+aged. A high frequency reciprocating rig was used to simulate fretting-type wear of these alloys at room temperature. The Vickers micro-hardness and wear rates were calculated and compared for each processing condition. It was determined that along with increasing hardness in the stir zones, FSP resulted in improved wear resistance for both alloys. Specifically, wear rates in the stir zones were reduced to lowest values of 1.6 x 10-5 and 5.8 x 10-7 mm3/N·m for the AR+FSP+aged Ti-185 and A-286 alloys, respectively, despite lower hardness for A-286 alloy. Mechanistic studies were conducted to determine the reason behind these improvements in wear resistance and the effect of FSP on the microstructural evolution during wear. For the Ti-185 alloy, x-ray diffraction revealed that there was a phase transformation from β-Ti (AR+FSP) to α-Ti (AR+FSP+aged). This phase decomposition resulted in the harder and stiffer Ti phase responsible for lowering of wear rate in Ti-185. While x-ray diffraction confirmed the A-286 alloy retains its austenitic structure for all conditions, scanning electron microscopy revealed completely different wear track morphology structures. There was increased coarse abrasion (galling) with the AR+aged A-286 alloy compared to the much finer-scale abrasion with the AR+FSP+aged alloy, which was responsible for smaller and less abrasive wear debris, and hence lower wear rate. Furthermore, cross-sectional focused ion beam microscopy studies inside the stir zone of AR+FSP+aged A-286 alloy determined that a) increased micro-hardness was due to FSP-induced microscopic grain refinement, and b) the corresponding wear rate decrease was due to even finer wear-induced grain refinement. With both effects combined, the level of damage and surface fatigue wear was suppressed resulting in lowering of the wear rate. In contrast, the absence of FSP-induced grain refinement in the AR+aged A-286 alloy resulted in lower hardness and increasing wear rate. In addition, micro-Raman spectroscopy inside the stir wear zone determined that the wear debris contained metal oxides of Fe3O4, Cr2O3, and NiO, but were a consequence and not the cause of low wear. Overall, FSP of titanium and stainless steel alloys resulted in lowering of wear rates suggesting it is a viable surface engineering technique to target and mitigate site-specific wear.

Physical Description

viii, 39 pages : illustrations (chiefly color)

Language

Collections

This thesis is part of the following collection of related materials.

UNT Theses and Dissertations

Theses and dissertations represent a wealth of scholarly and artistic content created by masters and doctoral students in the degree-seeking process. Some ETDs in this collection are restricted to use by the UNT community.

What responsibilities do I have when using this thesis?

When

Dates and time periods associated with this thesis.

Creation Date

  • May 2015

Added to The UNT Digital Library

  • Feb. 9, 2016, 4:37 p.m.

Description Last Updated

  • March 10, 2017, 2:49 p.m.

Usage Statistics

When was this thesis last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 249

Interact With This Thesis

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Tinubu, Olusegun Olukunle. Effect of Friction-stir Processing on the Wear Behavior of Titanium (Ti-1Al-8V-5Fe) and Stainless Steel (A-286) Alloys, thesis, May 2015; Denton, Texas. (digital.library.unt.edu/ark:/67531/metadc801955/: accessed July 22, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .