热机械处理对Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr铝合金固溶时效态组织及力学性能的影响  

Effect of Thermomechanical Treatment on Microstructure and Mechanical Property of Solution-aged Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr Aluminum Alloy

作　　者：张景玉[1] 许晓静[1] 阮鸿雁[1] 马文海[1] 王子路[1] 郭云飞[1] 

机构地区：[1]江苏大学先进制造与现代装备技术工程研究院,江苏镇江212013

出　　处：《稀有金属材料与工程》2017年第10期3033-3037,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学资金(51074079);江苏省高校科研成果产业化推进项目(JH10-37);江苏高校优势学科建设工程项目;江苏省高校研究生科研创新计划(CXLX12-0620)

摘　　要：以固溶-时效和热机械处理(TMT)(固溶-过时效-热压缩)-固溶-时效加工的超高强铝合金Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr为实验对象,分别采用电子背散射衍射(EBSD)、X射线衍射(XRD)、硬度测试和拉伸试验研究合金组织晶粒晶界特征分布、内部的位错密度和力学性能,并定量计算位错强化和晶界强化值。结果表明:热机械处理对合金晶粒细化影响不显著,平均晶粒尺寸从7.30μm减小至6.04μm,晶界角度从21.45?下降到21.04?,小角度晶界比例从0.588下降到0.546;TMT使峰时效硬度从2146 MPa(120℃/48 h)提高到2268 MPa(100℃/48h),但对强度影响较小,二者屈服强度均为600 MPa左右,拉伸断口均为沿晶和撕裂混合断裂。合金分别经固溶及TMT-固溶后,晶界位错密度均为零,TMT使位错强化与晶界强化的总强化从58.8 MPa下降到57.4 MPa。Ultra-high strength aluminum alloy Al-10.78Zn-2.78Mg-2.59Cu-0.22Zr-0.047Sr was treated by the process of solution-aging and thermomechanical treatment（TMT）（solution-overaging-hot compression）-solution-aging. Electron back scattering diffractions（EBSD） technology, X-ray diffraction（XRD）, hardness test and tensile testing were used to study the distribution of grain and grain boundaries, internal dislocation density and tensile properties, and the dislocation strengthening and grain boundary strengthening were calculated quantitatively. The results show that TMT refines grain with average grain size from 7.30 μm to 6.04 μm and reduces misorientation angle from 21.45°to 21.04°. TMT increases peak aging hardness from 2146 MPa（120 °C/48 h） to 2268 MPa（100 °C/48 h）, but has little effect on strength with both yield strength almost 600 MPa. The tensile fracture morphologies of alloys both display intergranular and tear fracture. Dislocation density of alloys processed by solution and TMT-solution are both 0, and TMT reduces sum of dislocation strengthening and grain boundary strengthening from 58.8 MPa to 57.4 MPa.

关 键 词：AL-ZN-MG-CU合金 热机械处理 组织 力学性能 位错强化 

分 类 号：TG146.21[一般工业技术—材料科学与工程]