Abstract
Laser surface alloying of SiC/Si3N4on AA6061 aluminium alloy was carried out using a 2-kW CW Nd-YAG laser. Different ratios of SiC and Si3N4powders were mixed and the layers were preplaced by pasting. Subsequent laser surface melting of the layers gave a surface metal matrix composite (MMC). The microstructure, chemical compositions and phase identification of the modified layers were examined using scanning electron microscopy (SEM), energy disperse X-ray spectroscopy (EDX) and X-ray diffractometry (XRD), respectively. The laser surface alloyed MMCs of AA6061-SiC and AA6061-Si3N4consisted of small amounts of Al4C3/Al4SiC4and A1N, respectively. For specimens alloyed with 100% Si3N4(AA6061-Si3N4), the cavitation erosion resistance R(e) was improved by three times as compared to the AA6061 alloy whereas there was no significant improvement in R(e) of the specimen alloyed with 100% SiC (AA6061-SiC). The surface hardness of the specimens alloyed with SiC/Si3N4was increased seven times. All the laser alloyed specimens with SiC/Si3N4showed a decrease in pitting resistance and absence of passivity owing to the aluminium-ceramic interfaces, which favour pit initiation or hindered passivity.
| Original language | English |
|---|---|
| Pages (from-to) | 11-20 |
| Number of pages | 10 |
| Journal | Surface and Coatings Technology |
| Volume | 132 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Oct 2000 |
Keywords
- Aluminum alloy
- Laser
- Si N 3 4
- SiC
ASJC Scopus subject areas
- Chemistry(all)
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry