ISSN:
1662-9752
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
The effect of particle size distribution and particle size ratio of SiCp in SiCp/SiO2preforms on the microstructure, microhardness of SiCp reinforcements, modulus of rupture,and superficial hardness of Al/SiCp composites produced by pressureless infiltration has beeninvestigated. SiCp/SiO2 preforms in the form of plates (4cm x 3cm x 0.5cm) have beenpressureless infiltrated by the alloy Al-15.52 Mg-13.62 Si (wt. %) at 1100 oC for 60 minunder inert atmosphere. SiC powders with average particle size of 10, 68 and 140 μm aremixed with SiO2 powders and preforms of 40 % porosity with unimodal, bimodal andtrimodal size distributions are prepared by uniaxial compaction. The bimodal (small: large)and trimodal (small: medium: large) preforms are prepared with different particle size ratiosin the following levels: 1:1, 3:1, 1:3, 2:2:2, 3:2:1, 3:1:2. Results from characterization byXRD, SEM and energy dispersive X-ray spectrometry show that the typical microstructure ofthe composites contains the MgAl2O4 (spinel), AlN and MgO phases formed duringprocessing as well as partially reacted silica, SiC, Si and Al. It is found that the density,reinforcement microhardness, modulus of rupture and superficial hardness of the compositesincrease all with wider particle size distribution. However, whilst the modulus of rupture ismainly affected on going from unimodal and bimodal to trimodal distribution, superficialhardness and microhardness are mostly influenced on going from unimodal to bimodal andtrimodal distribution
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.560.115.pdf
