Microstructure features and mechanical/electrochemical behavior of directionally solidified Al−6wt.%Cu−5wt.%Ni alloy  

定向凝固Al−6%Cu−5%Ni合金的显微组织特征和力学、电化学行为

作　　者：Adilson Vitor RODRIGUES Thiago Soares LIMA Talita Almeida VIDA Crystopher BRITO Amauri GARCIA Noé CHEUNG 

机构地区：[1]Department of Manufacturing and Materials Engineering,University of Campinas-UNICAMP,Campinas,SP,13083-860,Brazil [2]Federal Institute of Education,Science and Technology of São Paulo-IFSP,Bragança Paulista,SP,12903-600,Brazil [3]São Paulo State University-UNESP,Campus of São João da Boa Vista,São João da Boa Vista,SP,13876-750,Brazil

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第6期1529-1549,共21页中国有色金属学报（英文版）

基　　金：CNPq-National Council for Scientific and Technological Development(Grant:407871/2018-7);CAPES-Coordenação de Aperfeiçoamento de Pessoal de Nível Superior,Brazil,for the financial support。

摘　　要：The effects of the addition of 5.0 wt.%Ni to an Al−6wt.%Cu alloy on the solidification cooling rate(T),growth rate(V_(L)),length scale of the representative phase of the microstructure,morphology/distribution of intermetallic compounds(IMCs)and on the resulting properties were investigated.Corrosion and tensile properties were determined on samples solidified under a wide range of T along the length of a directionally solidified Al−6wt.%Cu−5.0wt.%Ni alloy casting.Experimental growth laws were derived relating the evolution of primary(λ_(1))and secondary(λ_(2))dendritic spacings with T and V_(L).The elongation to fracture(δ)and the ultimate tensile strength(σ_(U))were correlated with the inverse of the square root of λ_(1) along the length of the casting by Hall−Petch type experimental equations.The reinforcing effect provided by the addition of Ni in the alloy composition is shown to surpass that provided by the refinement of the dendritic microstructure.The highest corrosion resistance is associated with a microstructure formed by thin IMCs evenly distributed in the interdendritic regions,typical of samples that are solidified under higher T.在Al−6%Cu合金中添加5.0%Ni(质量分数),研究其对合金凝固时的冷却速率(T)和生长速率(V_(L)),显微组织中枝晶长度、金属间化合物(IMCs)的形貌和分布,以及最终性能的影响。研究在大冷却速率范围内制备的定向凝固Al−6%Cu−5.0%Ni合金铸锭沿长度方向的耐腐蚀性和拉伸性能。推导出一次枝晶间距(λ_(1))和二次枝晶间距(λ_(2))随T和V_(L)的演变规律。采用Hall−Petch公式计算沿铸件长度方向的断后伸长率(δ)和极限抗拉强度(σ_(U))与λ_(1)^(−1/2)的关系。在合金成分中添加Ni的强化效果优于细化枝晶组织的强化效果。在较高T下凝固的样品中形成细小的IMCs,且均匀分布在枝晶间,这种典型的显微组织使样品具有最高的耐腐蚀性。

关 键 词：Al−Cu−Ni alloys as-cast microstructures dendritic spacings tensile properties corrosion resistance 

分 类 号：TG146.21[一般工业技术—材料科学与工程]