Naslov
Mechanical properties and dry sliding wear behaviour of extruded Al-Al2O3 PM composites

Autori
K.Miloš, H.danninger, G.Jangg, H.-P.Degisher

Izvornik
Powder metallurgy progress (1335-8987) 9 (2009), 4; 191-204

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Al-matrix composites; alumina particle reinforcement; powder metallurgy; extrusion; dry sliding wear

Sažetak
Particle reinforced Al base MMCs offer improved mechanical properties and wear resistance compared to monolitihic Al alloys. In the present work, Ai-Al2O3 composites are produced by hot extruding green powder compacts of plain Al with 20..50wt%(14, 5..40, 3vol.%)fused alumina. The extruded bars are free of any macrodefects and are characterized mechanically and microstructurally.The dry sliding wear is studied on a pin-on-disc tester in dry run against ball bearing steel. With increasing content of hard phase the tensile and yield strengt as well as Youngs modulus first increase but tend to drop up 30vol.%particles, as a consequence of increasing probability of direct oxide-oxide contacts to be regarded as a defects. The wear behaviour, in contrast, exibits a consistently decreasing wear rate with higher hard phase content.Generally, the wear rate is affected markedly more by the test parametars, i.e.normal load and sliding speed, than by the microstructure. A pronounced transition from mild to severe wear is encountered when exceding a critical combination of parameters, as a consequence of thermal overloading of the matrix.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo, Metalurgija

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