PREDICTION OF STRESS - STRAIN BEHAVIOR IN SHORT FIBER METAL MATRIX COMPOSITES

The advanced technology applications in aerospace engineering utilize the temperature -resistant materials with high stiffness and strength coupled with light weight. The design of such materials is highly demanded due to the increasing aerospace challenges. Short - fiber reinforced metal matrix composites (SFRMMC) were found attractive. Among the (SFRMMC), the aluminum alloys reinforced with silicon carbide whiskers produced from low cost rice hulls represent an interesting class . They showed an improvement in strength stiffness , fatigue and creep of fifty to one hundred percent over unreinforced alloys. The present model predicts much better values for the stress - strain behavior of SiC(w) / 6061 Al composite than those reported by previous theoretical models. The strength of the composite increases with the increase in whiskers content and aspect ratio. An optimum value for the ductility of the heat - treated composite is obtained with aspect ratio 8 and 20 wt. %. The ductility always decreases with the increase in strength. The increase in composite strength over the matrix alloy is (56-167) %. With heat - treatment, the strength of the alloy is increased by 150 % and ductility is decreased by 43 %, while the strength of the composite is increased by (40-170) % and the ductility is decreased by (60-90) % for the chosen range of whiskers aspect ratios and contents. The bridging areas