Fracture behavior of magnesium alloys – Role of tensile twinning. (1st August 2015)

• Record Type: Journal Article
• Authors: Prasad, N. Subrahmanya; Naveen Kumar, N.; Narasimhan, R.; Suwas, S.
• Is Part Of: Acta materialia. Volume 94(2015)
• Page Start: 281
• Page End: 293
• Publication Date: 2015-08-01
• Subjects: Magnesium alloy -- Fracture behavior -- Tensile twinning -- Ductile failure -- Toughening mechanism; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2015.04.054
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: In this work, Mode-I fracture experiments are conducted using notched compact tension specimens machined from a rolled AZ31 Mg alloy plate having near-basal texture with load applied along rolling direction (RD) and transverse direction (TD). Moderately high notched fracture toughness of JC ∼ 46 N/mm is obtained in both RD and TD specimens. Fracture surface shows crack tunneling at specimen mid-thickness and extensive shear lips near the free surface. Dimples are observed from SEM fractographs suggesting ductile fracture. EBSD analysis shows profuse tensile twinning in the ligament ahead of the notch. It is shown that tensile twinning plays a dual role in enhancing the toughness in the notched fracture specimens with reduced triaxiality. It provides significant dissipation in the background plastic zone and imparts hardening to the material surrounding the fracture process zone via operation of several mechanisms which retards micro-void growth and coalescence.