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1、ELSEVIER PressScienceDirectTransacfions of NonferrouK Mctuh Society uf Chinawww AAvailable online at Trans. Nonferrous Met. Soc. China 28(2018) 1094 - 1102Effect of deformati on mode, dyn amic recrystallizatio n andtwi nning on rolli ng texture evoluti on of AZ31 magn esium alloys1 2Li-li GUO , Fumi
2、o FUJITA1. Engin eeri ng Research Cen ter of Con tin uous Extrusi on, Dalia n Jiaot ong Uni versity, Dalia n 116028, China;2. Department of Metallurgy, Graduate School of Engineering, Tohoku University, Aoba, Sendai, 980-8579, JapanReceived 20 March 2017; accepted 18 September 2017Abstract: In order
3、 to obtain quantitative relationship between (0002) texture intensity and hot rolling conditions, conventional rolling experiments on AZ31 magnesium alloys were performed with 20% - 40% reductions and temperatures within the range of 300- 500 C. Shear strain and equivalent strain distributions along
4、 the thickness of the rolled sheets were calculated experimentally using embedded pin in a rolling sheet. Rolling microstructures and textures in the sheet surface and center layers of the AZ31 alloys were measured by optical microscopy (OM), X-ray diffractometry (XRD) and electron back scatter diff
5、raction (EBSD). Effects of the rolling strain, dynamic recrystallization (DRX) and twinning on the texture evolution of the AZ31 alloyswere investigatedquantitatively. It is found that the highest (0002) basal texture intensities are obtained at a starting rolling temperature of 400 under the same s
6、train. Strain- temperature dependency of the (0002) texture intensity of the AZ31 alloy is derived.Key words: magnesium alloy sheet; hot rolling; texture; dynamic recrystallization; twinning1 In troducti onMagn esium and its alloys have con siderable pote ntial as structural materials in various in
7、dustrial fields, such as automobile and electro nic products 1. However, these metals have not yet bee n fully developed because of their limited cold formability and ductility. The poor cold formability of existing magnesium alloys is mainly caused by their str ong basal texture 2, because basal te
8、xture in duces high n ormal ani sotropy in a sheet and in creases the difficulty in deformati on accompanied by thickness reduction. This characteristic remarkably restricts the applications of these alloys in the form of sheets 3 - 5.It is well known that shear deformati on can modify (0001) basal
9、texture. Normal rolli ng in cludes two deformati on modes, n amely, compressi on and shear. The compressi on stra in is uni form along the sheet thick ness directi on. The shear stra in is the largest on the sheet surface but zero at the sheet cen ter. Con seque ntly, deformati on modes lead to diff
10、ere nt textures at various thick ness locati ons of rolled sheet. However, some studies on texture evoluti on duri ng rolli ng are characterized by the abse nee of deformati on mode and qua ntitative rolli ng stra in 6,7. On the other hand, rolli ng temperature is ano ther importa nt parameter that
11、can in flue nce the textural evoluti on in AZ31 alloys. High rolli ng temperature has a remarkable effect on weake ning the basal texture inten sity 5. The weake ning of the basal texture at high temperature deformati on has bee n suggested to be caused by dyn amic recrystallizati on (DRX) or rotati
12、 onal dyn amic recrystallizatio n (RDRX) 8,9. Nevertheless, these rolli ng tests are con ducted in multi-passes with differe nt reducti ons per pass, result ing in differe nces not only in the stra in but also in the rolling temperature at various sheet thickness locations. Consequently, various tem
13、peratures and strain con diti ons lead to differe nt DRX microstructures which may in flue nce the microtextural evoluti on. Weake ning the (0002) basal texture inten sity and improvi ng grain refinement by DRX during hot rolling process are some of the main purposes. However, little information is
14、available un der the qua ntitative roll ing con diti ons required to obta in con trolled texture in AZ31 alloy duri ng hot roll ing process.In this study, in order to exam ine the qua ntitative relati on ship betwee n the basal texture inten sity and theFoundation item: Project (51401043) supported by the National Natural Science Foundation of ChinaCorresponding author: Li-li GUO; Tel: +86-411-84106527; E-mail: DOI: 10.1016/S1003-6326(18)64745-4
