Cu-2.0Fe合金等温处理过程中富Fe析出相的形态演变  

Morphological Evolution of Fe-Rich Precipitates in a Cu-2.0Fe Alloy During Isothermal Treatment

作　　者：陈凯旋 李宗烜 王自东[1,2] Gilles Demange 陈晓华 张佳伟[1] 吴雪华[1] Helena Zapolsky CHEN Kaixuan;LI Zongxuan;WANG Zidong;Gilles Demange;CHEN Xiaohua;ZHANG Jiawei;WU Xuehua;Helena Zapolsky(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China;Group of Materials Science,University of Rouen Normandy,76801 Saint-Etienne du Rouvray,France)

机构地区：[1]北京科技大学、材料科学与工程学院,北京100083 [2]北京科技大学、新金属材料国家重点实验室,北京100083 [3]Group of Materials Science,University of Rouen Normandy,76801 Saint-Etienne du Rouvray,France

出　　处：《金属学报》2023年第12期1665-1674,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.52101119;北京市自然科学基金青年项目No.2214072;北京科技大学青年教师学科交叉研究项目(中央高校基本科研业务费专项资金)No.FRF-IDRY-20-034;中央高校基本科研业务费专项资金项目No.00007490。

摘　　要：研究了Cu-2.0Fe(质量分数,%)合金中富Fe析出相形态的演变行为及其与等温温度和保温时间的关系。结果表明,Cu-2.0Fe合金在Fe相fcc温区内的924、964和984℃保温时,富Fe相粗化并伴随着球状(纳米级)→立方状(亚微米级)→四分支花瓣状(亚微米级)→多分支花瓣状(微米级)的形态演变。随着等温温度和保温时间的增加,多分支花瓣状颗粒的尺寸逐步增大,分支数量逐步增加。多分支花瓣状颗粒的长大需要吞噬周边的小颗粒,导致温度升高时纳米~亚微米级富Fe颗粒的数量密度下降。基于相场模拟的分析表明,界面能、弹性能和化学驱动力的综合作用诱发富Fe相的多重形态演变,其中四分支花瓣状颗粒长大过程中,在弹性应变能和化学驱动力相互角逐作用下,从一次分支上生长出二次分支,进而产生了多分支花瓣状的形态。The morphology of precipitates changes during coarsening regimes,thereby resulting in the modification of mechanical properties of metallic materials.Hence,understanding the morphological evolution in precipitates is critical to tailor the macroscopic properties of industrial alloys.In particular,the morphology of Fe-rich precipitates in Cu alloys is complex,and it evolves from sphere to cube to petal and finally splits,which has been observed during casting and furnace cooling.However,morphological changes in Fe-rich precipitates during isothermal treatment remain unclear;thus,revealing the mechanism of morphological evolution is necessary.In this study,the relationship among the morphological evolution behavior of Fe-rich precipitates in Cu-2.0Fe(mass fraction,%)alloy,temperature,and time under different isothermal-treated processes was analyzed using SEM and TEM coupled with phase-field modeling.Results show morphology changes from a sphere in nanoscale to a cube in submicron scale to a four-branched petal in the submicron scale,and to a multi-branched petal in micron scale during coarsening of Fe-rich precipitates in Cu-2.0Fe alloy isothermally treated at 924,964,and 984oC(i.e.,the temperature range of the fcc Fe phase).The size of multi-branched petal-like Fe-rich precipitates and the number of branches increase with the increase of isothermal temperature and holding time.During coarsening of multi-branched petal-like precipitates,the surrounding small Fe-rich precipitates are engulfed,and thence the number density of the smaller ones in nano and submicron scales decreases when the temperature increases.The modeling result elucidates the multiple morphological evolution of Fe-rich precipitates,which is identical to the experiments,under the effects of interfacial energy,elastic energy,and chemical driving force.In particular,the combined effect of the latter two energies induces the initiation and growth of secondary branches out of primary branches in the four-branched petals,thereby producing multi-branche

关 键 词：铜合金 析出相 形态演变 材料表征 相场模拟 

分 类 号：TG166.2[金属学及工艺—热处理]