Role of atomic scale interfaces in the compressive behavior of carbon nanotubes in composites

The Overall Effects of AlN Nanoparticle Addition to Hybrid Magnesium Alloy AZ91/ZK60A

“…Regarding the trend in compressive failure strain, compressive shear buckling of Mg-Zn nanorods within the AZ91/ZK60A matrix (see Figure 5) aided in dispersing localized stored energy during compressive deformation. This allowed AZ91/ZK60A/1.5 vol% AlN to globally absorb relatively large amounts of strain energy during compressive deformation [12,36]. Here, Mg-Zn nanorod buckling within the AZ91/ZK60A matrix is a compressive toughening mechanism.…”

Carbon Nanotube Addition to Simultaneously Enhance Strength and Ductility of Hybrid AZ31/AA5083 Alloy

“…The tensile/compressive strength increase in AZ31/AA5083/1.0 vol.% CNT compared to monolithic AZ31/AA5083 was despite compressive shear buckling of CNT in AZ31/AA5083/ 1.0 vol.% CNT as illustrated in Figure 5. Here, the CNT (with aspect ratio as high as 100 [22]) is prone to buckling followed by fracture within the AZ31/AA5083 matrix during compressive deformation [37][38][39]. CNT buckling within the AZ31/AA5083 matrix occurs more easily with increasing CNT aspect ratio (or slenderness ratio) [39,40].…”

“…Here, the slightly increased tensile/compressive yield stress anisotropy can be attributed to compressive shear buckling of CNT as illustrated in Figure 5. The CNT is prone to buckling followed by fracture within the AZ31/AA5083 matrix during compressive deformation unlike during tensile deformation [37][38][39][40].…”

“…Compared to monolithic material, tensile and compressive failure strains were enhanced by 38% and 23% (respectively) in AZ31/AA5083/1.0 vol.% CNT. The failure strain increase in AZ31/AA5083/1.0 vol.% CNT compared to monolithic AZ31/AA5083 can be attributed to the following factors pertaining to reinforcement: 1) Presence and reasonably uniform distribution of CNT nanoparticles [31,43] and 2) Compressive shear buckling of CNT (regarding compressive failure strain only) [37][38][39][40]. In the case of reasonably uniform distribution of CNT nano- particles, it has been shown in previous studies that nanoparticles provide sites where cleavage cracks are opened ahead of the advancing crack front.…”

“…In the case of compressive shear buckling of CNT, CNT buckling within the AZ31/AA5083 matrix aids in dispersing localized stored energy during compressive deformation. This allows AZ31/AA5083/1.0 vol.% CNT to globally absorb relatively large amounts of strain energy during compressive deformation [37][38][39][40]. Here, CNT buckling within the AZ31/AA5083 matrix is a compressive toughening mechanism.…”