Hot Compressive Deformation of Rheocast AZ31 Magnesium Alloy

Abstract

The billet of magnesium AZ31B was made by twin-screw rheo-cast, and the specimen cut from the rheo-cast billet and normal cast billet were compressed in Gleeble-3000 hot simulator. The deformation temperature was 300, 350, and the strain rates were 0.001~1s-1. The relationship among flow stress, deformation temperature and strain rates were analyzed. The variation of the microstructure was observed and compared after the specimen was hot compressed. The results show that the surface of the rheo-cast specimen is much more smooth than the normal cast specimen after the compression. The dynamic recrystallization had taken place during the compression and the recrystallized grain of rheo-cast sample is more tiny than normal cast specimen.

Hot working and crystallographic texture analysis of magnesium AZ alloys

“…8 If the basal plane is perpendicular or almost parallel to the loading axis, the shear stress falls to very low value and a large force is needed to initiate slip. At high temperatures (.225uC), the pyramidal planes 10-11 È É get active as slip planes with [11][12][13][14][15][16][17][18][19][20] Â Ã as the direction of slip. The 10 -11 È É are the second most closely packed structures after the basal plane.…”

“…The DDRX process in AZ31 alloy has been investigated by many authors. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][27][28][29][30][31][33][34][35] In this process, finer grain size results in lower deformation stress, which is an effect opposite of the Hall-Petch law. Researchers have reported this phenomenon in pure Mg at temperatures greater than 350uC.…”