Microstructural and textural evolution during large strain hot rolling (LSR) of Mg–Al (AZ31) alloy

This study was aimed at revealing the influence of Al and Zn additions on microstructure, texture evolution and mechanical properties of twin roll casting Mg during multi-pass hot rolling. Firstly, both pure Mg and AZ31 sheets were rolled 9 passes with ∼80% thickness reduction. More effective grain refinement in AZ31 compared to pure Mg after hot rolling, which caused by the pinning effect from fine Mg17Al12 particles present in AZ31 alloy. Meanwhile a strong basal texture gradually formed with increasing thickness reduction in pure Mg. With Al and Zn adding, the texture intensity of AZ31 was much lower than pure Mg in each rolling-pass. The 5th AZ31 sample features a maximum intensity of ∼12.9, which is reduced by 50.6% as compared to the value of ∼26.1 for pure Mg. Compared to pure Mg, the Al and Zn solutes and weakened texture in AZ31 favor the strong work hardening, which promotes a simultaneous high ultimate tensile strength of ∼270 MPa and ductility of ∼22% in the 5th AZ31 sample. The results will be helpful for the TRCed Mg alloys with huge potential for industrial application.

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Deformation Behaviour of AZ31 Magnesium Alloy Sheets Produced by Twin-Roll Casting and Sequential Hot Rolling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.299-300.368 ◽

2011 ◽

Vol 299-300 ◽

pp. 368-371 ◽

Cited By ~ 2

Author(s):

Yan Dong Yu ◽

Peng Jiang ◽

Chao Li ◽

Kai Lin

Keyword(s):

Strain Rate ◽

Hot Rolling ◽

Az31 Alloy ◽

Grain Boundary Sliding ◽

Uniaxial Tensile ◽

Twin Roll Casting ◽

Roll Casting ◽

Deformation Properties ◽

Increasing Temperature ◽

Twin Roll

AZ31 alloy sheets were produced by twin-roll casting (TRC) and sequential hot rolling. Uniaxial tensile tests were used to evaluate the deformation properties of the AZ31 alloy at a strain rate of 7×10-4s-1 and a temperature range from room temperature to 400°C. The microstructure evolution and fracture behaviour were observed by optical microscopy and scanning electronic microscope. The results show that the elongation of the AZ31 alloy increases with increasing temperature at a strain rate of 7×10-4s-1. The AZ31 alloy begins to exhibit superplasticity at 300°C. The elongation of 497.8% is achieved at 400°C. The deformation of the AZ31 alloy at low temperature is controlled by dislocation motion, and with increasing temperature (above 300°C), grain boundary sliding (GBS) begins to play a dominant role during superplastic deformation.

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An Investigation of the Effect of Speeds of Work Rolls on Rolling Strip

Journal of Engineering Materials and Technology ◽

10.1115/1.2804549 ◽

1995 ◽

Vol 117 (3) ◽

pp. 341-346 ◽

Cited By ~ 4

Author(s):

Zone-Ching Lin ◽

Y. C. Cheng

Keyword(s):

Hot Rolling ◽

Rolling Force ◽

Large Strain ◽

Work Roll ◽

Rolling Process ◽

Analysis Model ◽

Hot Rolling Process ◽

Rolling Strip ◽

Work Rolls ◽

Thermoelastic Plastic

The paper is an investigation of strip curvature caused by the different speeds between the upper work roll and the lower work roll in the rolling process for an aluminum strip. At the same time, we analyzed the variations in the temperature field and strain field, and used a method of speeds variation of the upper and lower work rolls to calibrate the deformation curvature caused by the coolant condition in the hot rolling process. Based on the large deformation-large strain theory, and by means of the Updated Lagrangean Formulation (ULF) and increment theory, a coupled thermoelastic-plastic analysis model for hot rolling process is thus constructed. At the same time the finite difference method was also used to solve the transient heat transfer equation. Finally, the numerical analysis method developed in this study was employed to analyze the changes in the aluminum strip’s temperature and other changes during rolling. In addition, the average rolling force obtained from the simulation was compared with that from the experiments. It verified that the model in this study is reasonable.

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