| In Situ Neutron Diffraction during Compression or Tension of Extruded Mg97Zn1Y2 Stefanus Harjo1; Kazuya Aizawa2; Wu Gong3; Takuro Kawasaki2; 1JAPAN ATOMIC ENERGY AGENCY, Naka-gun, Japan; 2JAPAN ATOMIC ENERGY AGENCY, Tokai-mura, Japan; 3KYOTO UNIVERSITY, Tokai-mura, Japan; PAPER: 239/Magnesium/Regular (Oral) SCHEDULED: 14:25/Thu. 24 Oct. 2019/Adonis ABSTRACT: Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy is a magnesium alloy with a duplex microstructure consisting of a long period stacking ordered (LPSO) phase and an alpha-Mg phase [1]. Kink deformation was observed in an as-cast Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy subjected to hot compression. The refinement of LPSO via kinking was found to be the reason for strengthening of the material from microscopy analyses [2]. Direct evidence, however, has shown that increase in strength via kinking has not been observed so far. In this work, in situ neutron diffraction was used to investigate the anisotropic deformation behavior of LPSO and alpha-Mg phases during uniaxial compression or tension in an as-cast Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy and an extruded Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy. The evolutions of phase stresses in both the LPSO and alpha-Mg phases were evaluated and discussed with the occurrences of twinning and kinking during compression or tension. The as-cast Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy was prepared by high frequency induction melting in a carbon crucible. The extruded Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy was prepared by hot extrusion at 623 K of a round bar of an as-cast Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> alloy at an extrusion ratio of 10 and a ram speed of 2.5 mm/s in the air. The in-situ neutron diffraction experiment during compression was carried out using TAKUMI of J-PARC and a cylindrical test piece having a length of 16 mm and a diameter of 8 mm. The peak positions and integrated peak intensities were evaluated from the obtained diffraction patterns and the evolutions of lattice strains. The texture was then estimated and the phase stresses were subsequently evaluated. The response of phase stress to the applied stress of alpha-Mg deviated from the linearity which describes a smaller value at the applied stress that is lower than the macroscopic yield stress for the as-cast alloy. The response obtained pretended to keep the linearity up to the macroscopic yield stress for the extruded alloy. The details will be presented. References: [1] Y. Kawamura et al., Material Transactions 42 (2001) 1172-1176.<br />[2] X.H. Shao, Z.Q. Yang, X.L. Ma, Acta Mater. 58 (2010) 4760-4771. |
