应变诱导析出对7050合金连续热变形组织的影响  

Effect of strain-induced precipitation on subsequent hot deformed microstructure of 7050 alloy

作　　者：郎玉婧[1] 崔华[2] 蔡元华[1] 张济山[1] 

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《中国有色金属学报》2012年第10期2726-2733,共8页The Chinese Journal of Nonferrous Metals

基　　金：新金属材料国家重点实验室自主课题资助项目(2008Z-13)

摘　　要：利用Gleeble 1500热模拟试验机、光学显微镜(OM)、X射线衍射仪(XRD)、透射电镜(TEM)和背散射衍射(EBSD),研究变形工艺对7050铝合金析出相颗粒的影响,以及应变诱导析出颗粒对连续热变形组织的影响。结果表明:变形可使析出相颗粒发生球化,低应变速率促使析出相颗粒细化和再析出,高应变速率则促使析出相颗粒回溶和粗化;在连续热变形过程中,应变诱导析出的细小球形颗粒仍大量弥散分布在合金中,尺寸略有长大,并且析出相颗粒钉扎位错和晶界,晶内取向差变大。变形条带晶粒被细化,合金基体中形成大量多边形亚结构,这可能对铝合金强度和断裂韧性的提高产生积极作用。The effect of deformation process on the precipitates and effect of strain-induced precipitation particles on the subsequent hot deformed microstructure of 7050 alloy were investigated by optical microscope （OM）, X-ray diffractometer （XRD）, transmission electron microscope （TEM） and electron backscattering diffractometer （EBSD） on a Gleeble-1500 thermo-mechanical simulator. The results indicate that the deformation can accelerate the spheroidization of the precipitates. The refinement and re-precipitation of the precipitates at low strain rate deformation, and the dissolution and coarsening of the precipitates at high strain rate deformation can be observed. A large number of small globular precipitates distribute dispersively in the alloy, and the size of the precipitates increases during the subsequent hot deformation. The precipitates can pin the dislocations and grain boundaries, and misorientation increases in the elongated grain interior. The ribbon deformed-grains are refined and many polygonal substructures form, which maybe have a positive effect to improve the strength and fracture toughness of aluminum alloys.

关 键 词：7050合金 应变诱导析出 热变形 析出相 

分 类 号：TG146.2[一般工业技术—材料科学与工程]