Microstructure and Texture Development during Melt Conditioned Twin Roll Casting and Downstream Processing in an AZ31 Magnesium Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 87-92 ◽  
Author(s):  
Yan Huang ◽  
Zhong Yun Fan

The novel melt conditioned twin roll casting (MCTRC) process, in which the melt is conditioned by intensive shearing prior to twin roll casting, has allowed magnesium sheets to be produced with a fine and uniform microstructure and substantially reduced segregations across the sheet thickness. It is thus possible to eliminate the extensive downstream processing via repetitive hot rolling, which is required after conventional twin roll casting, and to produce sheets to the required thickness for forming. The present work was conducted to study the feasibility of producing magnesium sheets ready for stamping by the MCTRC process, focusing on the development of microstructures and textures. An AZ31 magnesium alloy was used in the investigation and MCTRC experiments were carried out to produce sheets of 6 mm and 2.5 mm in thickness respectively. After MCTRC, the 6 mm sheet was processed following the conventional procedures via homogenization, hot rolling and annealing, whereas the 2.5 sheet was only homogenized. Experimental results showed that: 1) the as-cast microstructures for both sheets were similalr in terms of grain size and distribution and their texture intensity and components were also similar, being dominated by basal components with a small fraction of primatic components; 2) downstream processing by hot rolling substantially intensified the basal textures for the 6 mm sheet; 3) the 2.5 mm sheet subjected only to homogenization after casting showed a grain structure similar to that obtained after repetitive hot rolling and annealing with substantially weakened textures. Mechanisms of texture formation and development during MCTRC and downstream processing are discussed in the paper.

2013 ◽  
Vol 27 (19) ◽  
pp. 1341020
Author(s):  
YANDONG YU ◽  
KAI LIN ◽  
PENG JIANG

In this paper, superplastic tensile testing and gas bulging forming of AZ31 and AZ31 + Y + Sr magnesium alloys produced by twin roll casting (TRC) and sequential hot rolling were carried out. At 673 K, the superplastic formability of the TRC AZ31 magnesium alloy sheets added Y and Sr elements has improved significantly compared to the common TRC AZ31 sheets. Formations of cavities on the bulging part go through three stages of the nucleation, growth and aggregation, finally cavities merging lead to rupture at the top of the bulging part.


2011 ◽  
Vol 43 (3) ◽  
pp. 1035-1047 ◽  
Author(s):  
I. Bayandorian ◽  
Y. Huang ◽  
Z. Fan ◽  
S. Pawar ◽  
X. Zhou ◽  
...  

2013 ◽  
Vol 765-767 ◽  
pp. 3176-3179 ◽  
Author(s):  
Yan Dong Yu ◽  
Qiong Hu ◽  
Peng Jiang

In this paper, the deformation properties of AZ31+Sr+Y magnesium alloy sheets produced by twin-roll casting (TRC) and sequential hot rolling were studied by the tensile testing at a strain rate of 7×10-4s-1and various temperatures: room temperature (RT), 200°C, 300°C and 400°C, respectively. The result shows that the microstructure of AZ31+Sr+Y alloy was refined obviously by adding elements Sr and Y, the elongation of the alloy increased with increasing temperature, and the fracture behavior of the alloy changed from brittle fracture to ductile fracture with increasing temperature. During the process of plastic deformation of AZ31+Sr+Y alloy, the twin plays a leading role at room temperature; the dislocation movement is regarded as the main deformation mechanism at 200° C; at the higher temperature (above 300°C) the grain boundary slip (GBS) plays a dominant role .


2020 ◽  
Vol 12 (5) ◽  
pp. 685-692 ◽  
Author(s):  
Jia Yao ◽  
Min Zha ◽  
Huiyuan Wang ◽  
Wei Lu

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.


2014 ◽  
Vol 81 ◽  
pp. 1553-1558 ◽  
Author(s):  
Kristina Neh ◽  
Madlen Ullmann ◽  
Rudolf Kawalla

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