摘要
通过Jmatpro热力学计算、光学显微镜(OM)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)研究了7175合金在加工过程中的组织演变。结果表明:7175铝合金热力学平衡相由Al Cr Mg Mn相、Mg2Si相、Al6Mn相、Al2Cu Mg相、Mg Zn2相和Al Cu Mg Zn相组成,实际状态下还含有少量的杂质相Al7Cu2Fe相。7175铝合金型材在挤压、固溶后组织主要为纤维状晶粒组织,没有明显的再结晶,在475℃下保温2.5 h后小尺寸的第二相基本回溶,大尺寸的未溶相为Al7Cu2Fe相和Mg2Si相,沿晶界呈链状破碎分布。弥散相Al Cr Mg Mn相在固溶和时效过程中一直存在,时效态晶内沉淀相为弥散分布的圆球状η′相和少量板状η相。晶界析出相MgZn2相断续分布,晶界无沉淀析出带(PFZ)宽度为35~45 nm。
The microstructure evolution of alloy 7175 during machining was studied by Jmatpro thermodynamic calculation,optical microscope(OM),scanning electron microscope(SEM)and transmission electron microscope(TEM).The results show that the ther⁃modynamic equilibrium phase of 7175 aluminum alloy is composed of AlCrMgMn phase,Mg2Si phase,Al6Mn phase,Al2CuMg phase,MgZn2 phase and AlCuMgZn phase,and there is a small amount of impurity phase(Al7Cu2Fe phase)in the actual state.After extrusion and solid solution,the microstructure of 7175 aluminum alloy profiles is mainly fibrous grain structure,without obvious recrystalliza⁃tion.After holding temperature at 475℃for 2.5 h,the second phase of small size is basically redissolved,and the undissolved phase of large size is Al7Cu2Fe phase and Mg2Si phase,which is distributed along the grain boundary in chain fracture.The dispersive phase AlCrMgMn is always present during solution and aging,and the precipitated phases in the aged state are spheroidη′phase and a small amount of tabularηphase.The precipitated phase MgZn2 is discontinuously distributed at the grain boundary,and the width of precip⁃itation-free zones at the grain boundary ranges from 35 nm to 45nm.
作者
汲庆涛
杨慧
赵忠超
史晓明
孙有政
Ji Qingtao;Yang Hui;Zhao Zhongchao;Shi Xiaoming;Sun Youzheng(Shandong Aluminum Alloy Pressure Processing Technology Innovation Center,Shandong Nanshan Institute of Science and Technology Co.,Ltd.,Longkou 264000;National Aluminum Alloy Pressure Processing Engineering Technology Research Center,Shandong Nanshan Aluminum Industry Co.,Ltd.,Longkou 264000;School of Engineering,Yantai Nanshan University,Longkou 264000,China)
出处
《铝加工》
CAS
2024年第1期14-18,共5页
Aluminium Fabrication
关键词
7175铝合金
纤维状晶粒组织
第二相
沉淀相
无沉淀析出带
7175 aluminum alloy
fibrous grain structure
second phase
precipitated phase
precipitation-free zones
