Deformation Behavior of Long-Period Stacking Ordered Structured Single Crystals in Mg85Zn6Y9 Alloy

• Published in: MATERIALS TRANSACTIONS Vol. 56; no. 7; pp. 952 - 956
• Main Authors: Mine, Yoji, Maezono, Ryo, Oda, Hiroaki, Yamasaki, Michiaki, Kawamura, Yoshihito, Takashima, Kazuki
• Format: Journal Article
• Language: English
• Published: Sendai The Japan Institute of Metals and Materials 01-01-2015; Japan Science and Technology Agency
• Subjects: Basal plane; Cleavage; Crystal structure; Crystallography; Crystals; Deformation; Directional solidification; magnesium alloys; microtension testing; Planes; plastic deformation; Shear stress; Single crystals; slip; Stacking; Stress-strain relationships; Stresses; twinning
• ISSN: 1345-9678; 1347-5320
• DOI: 10.2320/matertrans.MH201415

Microtension tests were performed on single crystals with different crystallographic orientations, which were prepared using an 18R-type long-period stacking ordered (LPSO) structure in a directionally solidified Mg85Zn6Y9 alloy. Anisotropic plasticity was observed for the LPSO phase specimens. Cleavage cracking occurred on the prismatic planes in a crystal with its loading direction parallel to the basal plane. The cleavage stress for the prismatic plane was determined to be approximately 460 MPa. A crystal that was oriented favorably for gliding on the basal plane exhibited a critical resolved shear stress of approximately 9.4 MPa. When a crystal was loaded along [0001], a sudden load drop was observed at a stress of approximately 250 MPa in the initial linear region of the stress–strain relation. Transmission electron microscopy results after the load drop showed that the deformation microstructure contained a twin-like boundary with a rotation axis along [11\bar{2}0].