Microstructural Studies of SiC/Al Alloys Metal Matrix Composites 
Jaroslaw Bienia$, Barbara Surowska 
Technical University of Lublin, Department of Materials Engineering, Poland 
Introduction 
Composite materials composed of a light matrix and highly resistant reinforcing elements can be 
widely applied in technology. Al, Ti, and Mg alloys can make suitable matrix materials in this type 
of composites. Whereas continuous and non-continuous fibres, whiskers and their particles are used 
as reinforcing elements [1, 5, 8]. 
The metallic matrix is reinforced in order to improve its properties to the level that could not be 
reached by any traditional methods that change monolithic structures [2]. Among the reinforcing 
phases mentioned above, SiC (Table 1) and Al,Os in the particle form are most widely applied. The 
technology of casting composite materials seems to be simple and cost-efficient. It enables 
manufacturing products of various shapes and sizes without an expensive and, in the case of 
composite materials, also quite difficult, finish. Hence, the method has good prospects for the 
future. 
Table 1: Characteristics of the reinforcement phase - SiC [2, 3,7] 
' Hardness | Density Specific Heat ~~ Thermal Conducitivity Soefhcient. Melting Point 
Moh’s | [g/em’] [J/kgK] [W/mK] bt [°C] 
x EA er MORE _ 
VLEs mie 90 | 32 840 13in 1100°C , 45 2200-27000 
f 10 nm. At first 
vanalyoit nf 
- ws he The subject of the examinations was a composite marked as F3S5.20S (Table 2) on base of Al 
! N system - Si (8,5-9% Si; 0,45-0,65 Mg) containing 20% of SiC. This material has been produced in 
0 resolve pores . . . ; . 
N N W the Foundry Research Institute in Cracow by the method of gravity casting and it was in non-heat 
vs N rel treatment state. This material can be applied as a modern construction material in automotive 
as en industry, particularly for brake discs. 
possible to 
glass ee Table 2: Some chosen physical and chemical properties of the F3S.20S composite after thermal 
age. In the ne treatment‘ [2]. 
ıidence that this i oo 
. Thermal Coefficient Tensile oo Unit Young's , 
ct Conducitivity | of Expansion | Strength ea Elongation Modulus nell 
g/m 1 | (Wicmk) | [109K] [MPa] Pal 1%), [GPa] | ards 
2,77 | 1.82 17.6 360 360 0.4 97 145 
esd from te J BA ! 
se anforcement ) precipitation hardening 
0 ? at 22°C 
" temperature range: 50-100°C 
The aim of conducted examinations was an estimation of basic stereological parameters 
particularly reinforcement phase SiC of composite F35.20S, evaluation of its structure related to its 
Sn application for brake discs. 
0001 139-144 
2000 
171