Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Mechanical Engineering | en_US |
| dc.contributor.advisor | Shi, San Qiang (ME) | - |
| dc.creator | Chen, Long | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/8048 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | - |
| dc.rights | All rights reserved | en_US |
| dc.title | Microstructure and mechanical properties of CrCuFeNi₂Tix high entropy alloys | en_US |
| dcterms.abstract | High entropy alloys (HEAs) have drawn much attraction from researchers in material field. In this thesis, reported studies and developments of HEAs are reviewed. Different from the traditional alloys which depend on one principal element, HEAs usually contain at least five principal elements. Based on their different compositions, HEAs show various unique properties, such as high hardness, good ductility, high heat resistance and high corrosion resistance, which are detailed discussed in the thesis. Varies of phases can form in difference HEAs, including BCC and FCC solid solution, intermetallic compounds and amorphous phase. It is very important to predict the phase formation of HEAs. In this thesis, some related rules are introduced, applied and proved. Based on the existing work, the mainly effects for HEAs are discussed from different perspectives, including thermodynamics, kinetics, and microstructures. The CrCuFeNi₂Tix HEAs (x=0.1-0.7) are prepared and studied. The XRD patterns of CrCuFeNi₂Tix HEAs prove the effectivities of ΔHmix, ΔSmix, δ, ΔX and VEC rules. Just like predicted by these rules, the pure FCC structure changes to FCC+BCC+Ni₃Ti gradually while the proportion of Titanium in HEAs increases. In this case, interesting variation trend of mechanical properties of CrCuFeNi2Tix HEAs is revealed. They show low stiffness and good flexibility. When x value is small, the HEAs show very good ductility, and when x value is large, the HEAs show very high hardness. The microstructures of CrCuFeNi₂Tix HEAs are observed after tensile test and hardness test. Due to the different values of x, both ductile fracture and brittle fracture would occur, while slip bands always can be found as an important characteristic of crystal plastic deformation. | en_US |
| dcterms.extent | xv, 89 leaves : illustrations ; 30 cm | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2015 | en_US |
| dcterms.educationalLevel | All Master | en_US |
| dcterms.educationalLevel | M.Sc. | en_US |
| dcterms.LCSH | Alloys | en_US |
| dcterms.LCSH | Alloys -- Mechanical properties. | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | restricted access | en_US |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b28179572.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 7.47 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/8048