Al-Nb-B细化剂形核质点的弥散化及其对铸造铝合金组织及力学性能的影响  

Homogenization of Nuclei in Al-Nb-B Inoculant and Its Effect on Microstructure and Mechanical Properties of Cast Al Alloy

作　　者：万杰 李皓天 刘书基 路洪洲 王立生 张振栋 刘春海 贾建磊 刘海峰 陈豫增[1] WAN Jie;LI Haotian;LIU Shuji;LU Hongzhou;WANG Lisheng;ZHANG Zhendong;LIU Chunhai;JIA Jianlei;LIU Haifeng;CHEN Yuzeng(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China;China International Trust and Investment Corporation Dicastal Co.Ltd.,Qinhuangdao 066011,China;China International Trust and Investment Corporation Metal Co.Ltd.,Beijing 100004,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]中信戴卡股份有限公司,秦皇岛066011 [3]中信金属股份有限公司,北京100004

出　　处：《金属学报》2025年第1期117-128,共12页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.52071262、52301197和52234009;中央高校基本科研业务费专项资金项目No.D5000240144;陕西省秦创原科学家+工程师项目No.2022KXJ-020;陕西省自然科学基础研究计划项目No.2023-JC-QN-0421。

摘　　要：Al-Nb-B细化剂兼具优异的组织细化效果和良好的抗Si毒化性能,是铸造铝合金的理想细化剂。为改善传统熔炼法所制细化剂母合金中形核质点分布不均匀的问题,本工作通过熔融盐反应制备细化剂母合金,从而使细化剂中形核质点弥散分布。结果表明,与传统的熔炼法相比,熔融盐反应法不仅促进了形核质点的弥散分布,还降低了细化剂中形核质点的平均尺寸(10μm→1μm),进而提高细化剂对铝合金晶粒尺寸的细化效率(34%→79%)。在此基础上,对铸态熔融盐细化剂进行了热挤压/冷轧变形处理,进一步提高了形核质点分布的弥散性,其中热挤压态细化剂的细化效果更好,且抗衰退性能优异。最终,研究了热挤压态熔融盐细化剂对铸造铝合金ZL104和ZL114A微观组织及力学性能的影响。结果表明,该细化剂将ZL104和ZL114A合金的晶粒尺寸分别细化79.2%和78.5%,并显著降低了合金的铸造缺陷,提高了塑性和冲击韧性,具有较高的工程应用价值。Silicon(Si)-containing aluminum(Al)alloys are highly valued in the fabrication of large-scale components with thin walls and complex geometries,such as automobile engine housings,gas turbine blades,and electrical equipment housings.These alloys are favored owing to their high fluidity,excellent filling ability,low risk of hot cracking,and excellent weldability.However,the broad solidification range of these alloys can lead to the formation of coarse primary Al dendrites and casting defects such as shrinkage porosity.To improve casting quality,inoculation is commonly carried out in practice.Numerous inoculants,such as Al-Ti,Al-B,Al-Ti-B,Al-Ti-C,and Al-Ti-B-C,have so far been developed.Among these,Al-Ti-B is widely adopted in industry owing to its high grain refinement efficiency.However,its efficiency decreases significantly when the Si content in Al alloys exceeds 5%(mass fraction),a phenomenon known as“Si poisoning”.To this end,an Al-Nb-B inoculant was developed to replace Al-Ti-B.Al-Nb-B demonstrates excellent grain refinement effect and effective resistance to Si poisoning,making it ideal for cast Al alloys with high Si contents.Typically,Al-Nb-B is fabricated using conventional casting methods with Al-Nb and Al-B intermetallic alloys as feedstocks.However,because these feedstocks have higher melting points than Al alloys,the reaction time required for the fabrication of Al-Nb-B is lengthy.This leads to the coarsening and sedimentation of nuclei in the molten Al,resulting in a nonuniform distribution in the as-cast inoculant,limiting its industrial application.To overcome this challenge,a fabrication method utilizing molten salt reactions has been proposed to homogenize the distribution of nuclei in Al-Nb-B inoculants.This approach not only improves the homogeneity of the nuclei but also reduces their average particle size from 10μm to 1μm.This is attributed to the relatively fast reaction rate between the molten salt and the liquid Al.As a result,the grain refinement efficiency improved significantly fr

关 键 词：铸造铝合金 细化剂 熔融盐反应 微观组织 力学性能 

分 类 号：TG292[金属学及工艺—铸造]