An Unusual Extrusion Texture in Mg-Gd-Y-Zr Alloys

• Published in: Advanced engineering materials Vol. 18; no. 6; pp. 1044 - 1049
• Main Authors: Alizadeh, Reza, Mahmudi, Reza, Ngan, Alfonso H. W., Langdon, Terence G.
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01.06.2016
• Subjects: Alloys; Extrusion; Magnesium base alloys; Precipitates; Precipitation; Rare earth metals; Surface layer; Texture
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201500516

Texture evolution is studied by EBSD in Mg–9Gd–4Y–0.4Zr (GW94), Mg–5Gd–4Y–0.4Zr (GW54), and Mg–5Gd–0.4Zr (GW50) alloys after processing with two extrusion‐ratios of 19:1 and 8:1. While the alloys show common extrusion textures at the low extrusion‐ratio of 8:1, an unusual extrusion texture is observed in the GW94 alloy at the high extrusion‐ratio of 19:1 with the (0001) basal planes aligned perpendicular to the extrusion axis. This unusual texture decreases at lower extrusion‐ratios and/or lower alloy contents. It is proposed that rare‐earth (RE) elements modify the texture by retarding recrystallization in solute drag effects on grain boundaries and pinning effects of RE‐rich precipitates. Textural study in Mg–Gd–Y–Zr alloys shows that while they exhibit common extrusion textures at the low extrusion‐ratio, an unusual extrusion texture is observed after high‐ratio extrusion. It is proposed that the RE elements modify the texture through retarding recrystallization by solute drag effects on grain boundaries and pinning effects of RE‐rich precipitates.