Addition of CNTs to enhance tensile/compressive response of magnesium alloy ZK60A

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

“…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]. This induces a significantly lower limit on the well known factors pertaining to reinforcement just listed.…”

“…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.…”

“…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.…”