双辊流变铸轧半固态AZ91D镁合金板坯的组织和织构  

Microstructure and Texture of Twin-rolling Semi-solid Rheo-rolling Casting AZ91D Magnesium Alloy Plate Slab

作　　者：李厅[1] 杨湘杰[1] 刘勇[1] 郭洪民[2] 程尚栩[2] 

机构地区：[1]南昌大学机电工程学院 [2]南昌大学材料科学与工程学院

出　　处：《特种铸造及有色合金》2011年第1期28-31,103,共4页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(50965015;51001058;50804023);教育部重点项目(205084)

摘　　要：采用LSPSF法制备出AZ91D镁合金半固态浆料,对其进行流变铸轧成板坯,利用金相观察、X射线衍射分析等方法对板坯的组织和织构进行了研究。结果表明,板坯中的物相主要由α-Mg和Mg17Al12组成;沿着铸轧方向(板坯纵向),由于半固态浆料中液相的流动速度比固相大,板坯纵向后端的初生相体积分数比前端更大,同时由于辊面对板坯的冷却作用,板坯的表面晶粒较芯部更细小。研究还发现,板坯横向中间位置上没有产生明显的(0002)基面织构现象,而在板坯横向边缘位置上,基体Mg锥面(101-1)与棱柱面(101-0)上所呈现的择优取向越来越明显。AZ91 Dplate slab was fabricated successfully by twin-rolling semi-solid rheo-rolling casting technology,in which semi-solid slurry was prepared by low superheat pouring with a shear field(LSPFS).Microstructure and texture of the semi-solid sheet slab were observed by OM(optical microscope)and XRD(X-ray diffraction).The results reveal that the sheet slab is composed of primary Mg phase and Mg17Al12 phase.Along the cast-rolling direction,volumetric fraction of primary phase in the back-end sheet slab is higher than that in the front-end as a result of flow velocity of liquid phase faster than solid phase in semi-solid slurry,meanwhile,grain size in the surface is finer than in the centre of the sheet slab because of cooling effects of roller face on sheet slab.Obvious(0002)basic plane texture is absent in the middle region of transverse sheet slab,while significant orientation of cone plane(1011)and prism plane(1010)at Mg matrix can be observed at edge position.

关 键 词：半固态 镁合金 流变铸轧 组织和织构 

分 类 号：TG292[金属学及工艺—铸造] TG339