过冷(Fe_(1-x)Co_(x))_(79.3)B_(20.7)合金的凝固  

Solidification of Undercooled(Fe_(1-x)Co_(x))_(79.3)B_(20.7) Alloys

作　　者：杨林[1] 马长松 刘连杰 李金富[1,3] YANG Lin;MA Changsong;LIU Lianjie;LI Jinfu(State Key Laboratory of Metal Matrix Composites,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Institute of Materials,China Academy of Engineering Physics,Mianyang 621907,China;Shanghai Key Laboratory of Materials Laser Processing and Modification,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学材料科学与工程学院金属基复合材料国家重点实验室,上海200240 [2]中国工程物理研究院材料研究所,绵阳621907 [3]上海交通大学材料科学与工程学院、上海市激光制造与材料改性重点实验室,上海200240

出　　处：《金属学报》2025年第1期99-108,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.52231002和51821001。

摘　　要：M_(23)B_(6)金属硼化物是很多金属材料中的强化相。为揭示该化合物相在Fe-Co-B合金中的形成问题,本工作采用熔融玻璃净化法进行了名义成分合金(Fe_(1-x)Co_(x))_(79.3)B_(20.7)(x=0~1)的深过冷凝固实验。研究发现:当x≤0.6时,随着过冷度的增加,初生相依次从M_(2)B、M_(23)B_(6)转变为α-M/M_(3)B,并且0.4<x≤0.6成分的合金存在L+M_(2)B→M_(3)B的包晶转变;对于x>0.6的合金,小过冷度下凝固的初生相为M_(3)B,随着过冷度的增加,初生相进一步从M_(2)B、M_(23)B_(6)向α-M/M_(3)B变化。随着Co含量增加,M_(23)B_(6)相析出的临界过冷度减小,M_(23)B_(6)相的稳定性提高。M-B(M=Fe,Co,Ni)alloys have garnered significant attention in the automotive,petrochemical,and power electronics industries owing to their excellent corrosion resistance,wear resistance,and high-temperature strength.The service performances of the M-B alloys are closely related to that of borides.Among them,M_(23)B_(6) generally exists as a metastable phase.However,the understanding of its formation is limited compared to that of other borides.To reveal the effect of Fe/Co content ratio on the solidification behavior of the Fe-Co-B alloys,particularly the formation of M_(23)B_(6) phase,alloys with nominal composition of(Fe_(1-x)Co_(x))_(79.3)B_(20.7)(x=0-1)were undercooled using the melt fluxing technique.Consequently,the solidification behaviors were systematically investigated.With the increase in the Co content,the stable eutectic reaction changed from L→α-M+M_(2)B for x<0.4 to L→α-M+M_(3)B for x>0.4.Consequently,the two eutectic reactions occurred at the same temperature at x=0.4,and a peritectic reaction L+M_(2)B→M_(3)B was observed at x>0.4.With the increase in the undercooling,the primary phase changes from M2B and M_(23)B_(6) to α-M/M_(3)B in the alloys with x≤0.6,and from M_(3)B,M_(2)B,and M_(23)B_(6) to α-M/M_(3)B in the alloys with x>0.6.The increase in Co content reduced the critical undercooling for the M_(23)B_(6) phase to precipitate primarily and improved its stability,that is,the primary M_(23)B_(6) phase decomposed into α-M/M_(2)B in the following cooling process when the Co content is not excessively high.However,it could sometimes be reserved to room temperature in case of a very large Co content.

关 键 词：Fe-Co-B 合金 过冷 非平衡凝固 相选择 

分 类 号：TG111.4[金属学及工艺—物理冶金]