Effect of SiC volume fraction and particle size on the fatigue resistance of a 2080 Al/SiC p composite

Abstract

The effect of SiC volume fraction and particle size on the fatigue behavior of 2080 Al was investigated. Matrix microstructure in the composite and the unreinforced alloy was held relatively constant by the introduction of a deformation stage prior to aging. It was found that increasing volume fraction and decreasing particle size resulted in an increase in fatigue resistance. Mechanisms responsible for this behavior are described in terms of load transfer from the matrix to the high stiffness reinforcement, increasing obstacles for dislocation motion in the form of S' precipitates, and the decrease in strain localization with decreasing reinforcement interparticle spacing as a result of reduced particle size. Microplasticity was also observed in the composite, in the form of stress-strain hysteresis loops, and is related to stress concentrations at the poles of the reinforcement. Finally, intermetallic inclusions in the matrix acted as fatigue crack initiation sites. The effect of inclusion size and location on fatigue life of the composites is discussed.

Effect of Reinforcement Clustering on Crack Initiation Mechanism in a Cast Hybrid Metal Matrix Composite during Low Cycle Fatigue

“…Microcracks were always initiated at the particle-matrix interfaces where an Al 2 O 3 whisker was also located very near to the crack initiated SiC particle (marked by W 1 in Figure 4). Previous researches reported that the main reason of microcrack initiation in the particulate or whisker reinforced system is debonding at the reinforcement-matrix interface [6,28,29]. The results obtained for hybrid MMC are consistent with these observations.…”

“…However in practice, it is often difficult to obtain a homogeneous distribution of reinforced particles or whiskers. Further, it has been found that the non-uniformity in the reinforcement arrangement can have significant effects on the mechanical properties of the MMCs [6,7]. Existing experimental and theoretical evidences suggest that the homogeneity of particles or whiskers spatial arrangement plays a key role in controlling the yield strength, ductility, fatigue and fracture behaviors of MMCs [8].…”

Microstructure-Based Computational Modeling of Mechanical Behavior of Polymer Micro/Nano Composites

“…The results of experimental data support this statement and reveal that the distribution of the reinforcing particles and the randomness pattern of the constituents can greatly influence the mechanical behavior of the composites (Chawla et al, 1998;Watt et al, 1996). Through extensive observations it is revealed agglomeration and network formation of the particles are responsible for the high levels of reinforcement, and also the breakdown of networks and the deagglomeration are the main source of the non-linear responses of strain (Heinrich et al, 2002;Kraus, 1984).…”

Fabrication, Charecterization and Development of High Damping Materials for Naval Applications

“…Lloyd D.J et al [3] studied the effect of particle induced damage in MMCs, with MMCs reinforced by particles with a size greater than 10µm, the dominant damage mechanism was cracking of particle and that the particle -matrix interface appeared to have little effect on the overall damage fracture behaviour. Chawla et al [4] showed that in 2080/SiC p composites with volume fractions ranging from 10 to 30 vol. %, particle cracking was observed above an average particle size of 20 µm.…”