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https://ptsldigital.ukm.my/jspui/handle/123456789/487044Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Mohd Zaidi Omar, Prof. Dr. | - |
| dc.contributor.author | Mnel A.H. Abdelgnel (P75372) | - |
| dc.date.accessioned | 2023-10-11T02:27:59Z | - |
| dc.date.available | 2023-10-11T02:27:59Z | - |
| dc.date.issued | 2019-05-09 | - |
| dc.identifier.other | ukmvital:121021 | - |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/487044 | - |
| dc.description | Thixoforming is considered a feasible technology to form alloys in a semisolid state into almost near net-shaped products. Even though there has been considerable research for the thixoforming process fundamental characteristics as well as their impact on the mechanical and microstructural properties of metals, only few studies have actually evaluated the tribological properties associated with thixoformed and rheocast Al-Si alloys. Thus, this thesis aims at examining the microstructural and dry sliding wear behaviours of thixoformed Al-5.7Si-2Cu-0.3Mg alloys and compare with the conventional mould cast alloy. The study also makes an effort to understand how the thixoforming process can affect the mechanical and microstructural properties of such alloys. A cooling slope technique was employed to create feedstock material for thixoforming under an argon gas atmosphere, where on an inclined plate that was fixed at a 60° slope angle, molten alloy is poured at different temperatures of 640ᵒC, 650ᵒC and 660ᵒC at lengths 300, 400 and 500 mm. Then, the as-cast alloys chemical composition was revealed through X-ray fluorescence. Solution heat treatments were carried out at 485°C and 500°C, at solution times of 2-12 hours. Optical microscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy and X-ray diffraction were employed to analyse the phase formation and microstructure of the alloys. Tensile and hardness tests were conducted to determine the mechanical properties. The tribological tests were performed by employing a pin-on-disc tribometer under dry sliding conditions with a fixed sliding speed of 1.0 m/s, under sliding distances of 1, 3 and 5 Km, loads of 10, 50 and 100 N and temperatures of 25°C, 150°C and 300°C. The results suggest that at 485 ± 5°C for 12 hours and ageing at 190°C for 10 hours, the optimum T6 treated was achieved. Applying T6 heat treatment resulted in macrohardness being 12% higher when compared to the conventional cast alloy. The microstructure of the Al-5.7Si-2Cu-0.3Mg thixoformed subjected to T6 heat treatment showed spheroidal α-Al grains with evenly distributed Si particles. A decrease in porosity had resulted in considerable increase in thixoformed-T6 samples density as well as hardness. The effect of rheocasting on the tribological properties of the alloy was also investigated and compared with the conventionally cast alloy. The rheocast process had decreased the specific wear rate and coefficient of friction by 22 % and 49 %, respectively, when sliding distance was 5 Km at 100 N. The thixoformed alloy subjected to the T6 heat treatment showed better wear resistance than those non-heat treated. The volume loss value of the thixoformed and thixoformed-T6 alloys is reduced by about 20% and 67% respectively compare with as-cast alloy. The specific wear rate increased at a high temperature and high sliding distance for all alloys due to the buildup of the transfer layer of the sample. Overall, the results of this work suggested that the Al-5.7Si-2Cu-0.3Mg alloy can be successfully used for thixoforming automotive components.,Ph.D. | - |
| dc.language.iso | eng | - |
| dc.publisher | UKM, Bangi | - |
| dc.relation | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | - |
| dc.rights | UKM | - |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertations | - |
| dc.subject | Dissertations, Academic -- Malaysia | - |
| dc.subject | Alloys | - |
| dc.subject | Microstructure | - |
| dc.subject | Aluminum | - |
| dc.title | Dry sliding wear behaviour of thixoformed AL-5.7SI-2CU-0.3MG aluminium alloy | - |
| dc.type | Theses | - |
| dc.format.pages | 216 | - |
| dc.identifier.callno | TA483.A2364 2019 3 tesis | - |
| dc.identifier.barcode | 005453(2021)(PL2) | - |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_121021+SOURCE1+SOURCE1.1.PDF Restricted Access | 14.92 MB | Adobe PDF |  View/Open |
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