Effects of dendrite cell size and particle distribution on the near-threshold fatigue crack growth behaviour of cast AlSiCp composites

• Published in: Acta materialia Vol. 44; no. 6; pp. 2249 - 2257
• Main Authors: Kumai, S., Hu, J., Higo, Y., Nunomura, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.1996; Elsevier Science
• Subjects: Applied sciences; Exact sciences and technology; Fatigue; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Crack opening displacement; Silicon carbide; Rupture; Mechanical properties; Fatigue; Aluminium; Experimental study; Microstructure; Composite material; Dispersion strengthened metal; Dendrite; Crack propagation
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/1359-6454(95)00357-6

Fatigue crack growth tests and crack closure measurements were performed for A356 cast aluminium alloys reinforced by 10 or 20% SiC particles and their matrix A356 alloys with systematically controlled dendrite cell size and particle distribution. The cell size dependence of the fatigue crack growth behaviour in the composite was found to be quite similar to that of the matrix alloy. This suggests that the cell size rather than the particle-crack tip interaction is the most important factor to control the fatigue crack growth of the composites. Near threshold fatigue crack growth properties were improved in the composites with coarser cell size and inhomogeneous particle distribution due to the enhanced roughness induced crack closure effect. These results were compared to those of powder-metallurgically-processed materials.