38 KB579 KB31 KB200020242012Májlinger, KornélOrbulov, Imre Norbertštevilka:4letnik:46str. 375-382ISSN:1580-2949COBISSID:937130URN:URN:NBN:SI:doc-L9TXPOGKenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijecompositeenergijsko disperzijska rentgenska spektroskopijaenergy dispersive X-ray spectroscopyfoamkompozitmicroballoonmicrospheremikrobalonimikrokroglicepenaMicrostructure of metal-matrix composites reinforced by ceramic microballoons| Mikrostruktura kompozitov s kovinsko osnovo, ojačano s keramičnimi mikrokroglicami|Metal-matrix composites reinforced by ceramic hollow microspheres were produced as special porous metals, called metal-matrix syntactic foams (MMSFs). In this paper the microstructure of the ceramic hollow microspheres as reinforcing elements is investigated in connection with the production of MMSFs with the pressure infiltration. SL150- and SL300-type ceramic microspheres from Envirospheres Ltd (Australia) were investigated. They contained various oxide ceramics, mainly Al2O3 and SiO2. The chemical composition and the microstructure of the microspheres had a strong effect on their infiltration characteristics; therefore, in the view of the MMSF production it was very important to know microstructural details about the microspheres. Due to this energy-dispersive X-ray spectroscopy, maps were recorded from the cross-sections of the microspheresć walls. The results showed that the Al2O3 and SiO2 distribution were not equal; the Al2O3 phase was embedded in the surrounding mullite, while the SiO2 phase occurred in the form of needles. Line energy-dispersive X-ray spectroscopy measurements were performed in order to investigate the possible reaction between different aluminium alloy matrices and the ceramic microspheres. The results showed that, due to an uneven distribution of Al2O3, rich particles of the molten aluminium could reduce the SiO2 rich parts of the microspheres and the walls of the hollow microspheres became damaged and degraded. This chemical reaction between the microspheres and the walls could make the infiltration easier, but the resulting mechanical properties will be reduced due to the damaged microsphere wallsKompoziti s kovinsko osnovo, ojačano s keramičnimi votlimi mikrokroglicami, sobili izdelani kot posebna porozna kovina z nazivom sintaktična pena s kovinsko osnovo (MMSF). V tem članku je opisana raziskava mikrostrukture keramičnih votlih mikrokroglic v povezavi z izdelavo MMSF z infiltracijo pod tlakom. Preiskovane so bile SL150- in SL300-keramične mikrokroglice proizvajalca Envirospheres Ltd (Avstralija). Vsebujejo različne keramične okside, večinoma Al2O3 in SiO2. Kemijska sestava in mikrostruktura mikrokroglic imata velik vpliv na sposobnost njihove infiltracije, zato je z vidika izdelave MMSF pomembno poznati podrobnosti mikrostrukture teh mikrokroglic. Zaradi tega je bila na prerezu stene mikrostrukturnih kroglic posneta razporeditev elementov z energijsko disperzijsko spektroskopijo. Rezultati kažejo, da razporeditev Al2O3 in SiO2 ni enaka: Al2O3-faza je vgrajena v obkrožajoči mulit, medtem ko se SiO2-faza pojavlja v obliki igel. Da bi preiskali morebitne reakcije med osnovo iz različnih aluminijevih zlitinin keramičnimi mikrokroglicami, je bila izvršena linijska energijsko disperzijska rentgenska spektroskopija. Rezultati so pokazali, da zaradi neenakomerne razporeditve z Al2O3 bogati delci v staljenem aluminiju lahko reducirajo s SiO2 bogata področja mikrokroglic, in stene votlih mikrokroglic postanejo poškodovane in degradirane. Kemijske reakcije med mikrokroglicami instenami lahko olajšajo infiltracijo, vendar pa se mehanske lastnosti poslabšajo zaradi poškodovanih sten mikrokroglicTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije