Surface analysis of industrial materials by synchrotron X-ray absorption spectroscopy
(2024) MMTM05 20241Production and Materials Engineering
- Abstract
- This thesis presents an in-depth investigation into the behaviour of two distinct industrial material systems under specialized conditions: diamond tools machining titanium alloys and the annealing of alumina-forming steels. The observation of two sub-projects was finished by two state-of-the-art synchrotron facilities FlexPES and MAXPEEM respectively at the MAX IV laboratory. The study elucidates the surface, chemical, and microstructural transformations that these materials undergo during machining and thermal treatment, providing insights into their potential industrial applications and limitations.
The first sub-project explored the feasibility of using diamond-cutting tools for machining titanium alloy Ti64. During the machining... (More) - This thesis presents an in-depth investigation into the behaviour of two distinct industrial material systems under specialized conditions: diamond tools machining titanium alloys and the annealing of alumina-forming steels. The observation of two sub-projects was finished by two state-of-the-art synchrotron facilities FlexPES and MAXPEEM respectively at the MAX IV laboratory. The study elucidates the surface, chemical, and microstructural transformations that these materials undergo during machining and thermal treatment, providing insights into their potential industrial applications and limitations.
The first sub-project explored the feasibility of using diamond-cutting tools for machining titanium alloy Ti64. During the machining process, the diamond tool undergoes graphitization, subsequently reacting with titanium to form a TiC layer on the rake face. This interaction results in a layered sandwich structure on the surface of the tool, consisting of a nanometre-thick titanium oxide film on top, a mixture of TiC and Ti64 in the middle, and diamond as the base material. The presence of graphite permeating through these layers indicates the graphitization of diamond tools. Oxygen-containing functional groups detected on the as-worn tool surface may suggest that oxidization is influenced by environmental moisture and not only by oxygen. This suggests that under both low and high cutting velocities, diamond tools may not be the most suitable for machining titanium alloys due to tool wear and chemical reactions.
The second sub-project focuses on the annealing behaviour of alumina-forming steels to study surface oxide integrity and compositional changes at a series of temperatures and high vacuum conditions. The results show that the Al2O3 oxide layer maintains its integrity up to 500 ℃ but begins to degrade beyond this temperature, exposing metallic grains at around 800 ℃. The presence of both oxidized and metallic aluminium varies with temperature, highlighting a non-uniform de-oxidation process influenced by grain orientation and microstructural features. Besides aluminium, findings also include the stability of iron in its metallic state throughout the annealing process and the temperature-dependent reduction of chromium oxide to metallic chromium at around 400 ℃. At 850 ℃, the formation of dendritic structures and changes in chromium and iron distribution suggest complex chemical interactions and structural transformations. These transformations are crucial for understanding the protective behaviour of chromium and developing new methods for joining or brazing alumina-forming steels. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9155546
- author
- Liu, Yining LU
- supervisor
- organization
- course
- MMTM05 20241
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Machining, PCD, Ti64, Chemical wear, Diffusion dissolution wear, Annealing, Deoxidation, Segregation, Alumina-forming steels, XAS, XPS
- report number
- CODEN: LUTMDN/(TMMV-5359)/1-101/2024
- language
- English
- id
- 9155546
- date added to LUP
- 2024-06-03 11:11:13
- date last changed
- 2024-06-03 11:11:13
@misc{9155546,
abstract = {{This thesis presents an in-depth investigation into the behaviour of two distinct industrial material systems under specialized conditions: diamond tools machining titanium alloys and the annealing of alumina-forming steels. The observation of two sub-projects was finished by two state-of-the-art synchrotron facilities FlexPES and MAXPEEM respectively at the MAX IV laboratory. The study elucidates the surface, chemical, and microstructural transformations that these materials undergo during machining and thermal treatment, providing insights into their potential industrial applications and limitations.
The first sub-project explored the feasibility of using diamond-cutting tools for machining titanium alloy Ti64. During the machining process, the diamond tool undergoes graphitization, subsequently reacting with titanium to form a TiC layer on the rake face. This interaction results in a layered sandwich structure on the surface of the tool, consisting of a nanometre-thick titanium oxide film on top, a mixture of TiC and Ti64 in the middle, and diamond as the base material. The presence of graphite permeating through these layers indicates the graphitization of diamond tools. Oxygen-containing functional groups detected on the as-worn tool surface may suggest that oxidization is influenced by environmental moisture and not only by oxygen. This suggests that under both low and high cutting velocities, diamond tools may not be the most suitable for machining titanium alloys due to tool wear and chemical reactions.
The second sub-project focuses on the annealing behaviour of alumina-forming steels to study surface oxide integrity and compositional changes at a series of temperatures and high vacuum conditions. The results show that the Al2O3 oxide layer maintains its integrity up to 500 ℃ but begins to degrade beyond this temperature, exposing metallic grains at around 800 ℃. The presence of both oxidized and metallic aluminium varies with temperature, highlighting a non-uniform de-oxidation process influenced by grain orientation and microstructural features. Besides aluminium, findings also include the stability of iron in its metallic state throughout the annealing process and the temperature-dependent reduction of chromium oxide to metallic chromium at around 400 ℃. At 850 ℃, the formation of dendritic structures and changes in chromium and iron distribution suggest complex chemical interactions and structural transformations. These transformations are crucial for understanding the protective behaviour of chromium and developing new methods for joining or brazing alumina-forming steels.}},
author = {{Liu, Yining}},
language = {{eng}},
note = {{Student Paper}},
title = {{Surface analysis of industrial materials by synchrotron X-ray absorption spectroscopy}},
year = {{2024}},
}