摘要
研究了釆用铜模喷铸制备的K424合金的组织及等温时效热处理工艺对其沉淀相析出行为的影响。结果表明,冷速的提高有利于合金枝晶组织的细化,其中二次枝晶间距由铸态时的96μm显著下降到快冷态的9μm,同时导致碳化物与共晶相的尺寸及含量降低。铜模喷铸合金经等温时效处理后,原始过饱和固溶体组织发生沉淀相析出。当时效温度为800℃时,γ′相的尺寸及体积分数均随保温时间的延长而增加,相应形貌由不规则球形向立方结构发生转变,沉淀强化效应的增强导致合金硬度不断提高。经1000℃/4 h时效处理后,铜模喷铸合金中γ′相为矩形形貌并发生明显粗化,从而引起合金硬度的下降。
Microstructure of K424 alloy prepared by copper mould spray casting was studied, and the effect of isothermal aging treatment on precipitation behavior of the alloy was investigated. The results show that the improvement of the cooling rate is beneficial to the refinement of the alloy dendritic structure, in which the secondary dendrite spacing is significantly reduced from 96μm in ascast to 9μm in the rapid cooling state, and at the same time, the size and the content of the carbide and the eutectic phase are reduced. After isothermal aging treatment, the precipitate phase of the primary supersaturated solid solution in the copper mould spray casting alloy is precipitated. When the isothermal aging temperature is 800℃,the size and volume fraction of γ′ phase of the alloy increase with the increase of the holding time, and its corresponding shape is changed from the irregular spherical to the cubic structure, and the enhancement of the precipitation strengthening effect results in an increase in the hardness of the alloy. After isothermal aging at 1000℃for 4 h, the γ′ phase in the copper mold spray casting alloy has a rectangular shape and is obviously coarsened, resulting in a decrease in the hardness of the alloy.
作者
雷四雄
杨伟
郑行
LEI Si-xiong;YANG Wei;ZHENG Hang(Zhuzhou AECC Power Precision Casting Limited Corporation,Zhuzhou 412002 ,China;National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology,Nangchang Hangkong University,Nanchang 330063 ,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2019年第7期45-52,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51461032)
江西省教育厅资助项目(GJJ180513)
关键词
非平衡凝固
时效
组织细化
沉淀相
高温合金
non-equilibrium solidification
aging
microstructure refinement
precipitation phase
superalloy
