Tensile and fatigue behavior of Al-based metal matrix composites reinforced with continuous carbon or alumina fibers: Part II. Quasi-unidirectional composite cross-ply laminates

Abstract

The mechanical behavior (tension, fatigue, and notch sensitivity) of Al-based metal matrix composite (MMC) cross-ply laminates is investigated. The two selected laminates, K139/A357 and N610/AU2, are reinforced by continuous K139 (carbon) or N610 (alumina) fibers. These multiplies consist in the stacking of (quasi-unidirectional) quasi-UD preforms oriented at 0, Ϯ45, and 90 deg, the thermomechanical behavior of the corresponding quasi-UD composites being reported independently (Part I). The investigated cross-ply laminates exhibit attractive static and cyclic performances and a low notch (circular hole) sensitivity. High-resolution microfractography has led to a better understanding of the fracture mechanisms of these materials. In this respect, the role of the transverse bundles is dominant in the tensile and fatigue failure of both laminates. However, the failure surfaces are completely different: long fiber pullout in the K139/A357 laminate and much more planar areas in the N610/AU2 laminate. Due to the rather low notch sensitivity, a large portion of the specimen section was already highly damaged during a nonnegligible part of the fatigue life: debonded interfaces in the K139/A357 laminate and multicracked and "crumbled" matrix in the N610/AU2 laminate. These mechanisms are in good agreement with the weak interface in the first case and the very low yield stress of the AU2 matrix, much lower than the fatigue limit of the N610/AU2 laminate, in the second case. Moreover, compared to the quasi-UD composites, the stress concentration around the notch allows further exacerbation of the fatigue mechanisms, much more intense than that attained in "model" composites.

Nanocarbon reinforced aluminium matrix (NRAM) composites: Fabrication, structure and properties

“…Two of commonly used reinforcing material types in metal matrix are ceramic and carbon-based material [25-29]. Metal matrix composites can be categorised into four subgroups depending on shape of reinforcing materials, such as particle reinforced metal matrix composite [30], continuous fibre reinforced metal matrix composite [31], short fibre or whisker reinforced metal matrix composite [32]and hybrid metal matrix composite with more than one type of reinforcements [33]. Mechanical properties of MMC depend on the type of matrix, type of reinforcement and their concentration, microstructure and fabrication process [34].…”

Analysis of active cooling through nickel coated carbon fibers in the solidification processing of aluminum matrix composites

“…Friction coefficient and wear loss decreased as the carbon fiber volume fraction increased [16]. Tensile and shear properties, fatigue performance, and fracture toughness of such composites are also investigated, specifically for the effect of interfacial bonding conditions on the mechanical properties of the composite [17][18][19][20][21]. Studies have shown that the heat treatment of the composite to achieve precipitation hardening in the matrix can lead to sufficient residual thermal stresses to damage the fibers [11].…”

Tensile and fatigue behavior of Al-based metal matrix composites reinforced with continuous carbon or alumina fibers: Part I. Quasi-unidirectional composites

“…Although the study of the mechanical properties and damage mechanisms of the quasi-UD composites represents a broader investigation involving acoustic emission monitoring, [10,11] only those of the results that are essential in the understanding of the specific behavior of this type of composite are reported in the present article (Part I). The next article (Part II [12] ) will be devoted to the quasi-UD (0, Ϯ45, 90 deg) laminates. Moreover, at a more theoretical viewpoint, due to the presence of the fibers and to the specific aspect of the quasi-UD preform, an exacerbation of the fatigue mechanisms occurring in the matrix, even more severe than in "model" UD composites, [13,14,15] may be expected.…”