E2EM’s prediction of LaB_(6) as nucleation substrate for primary Mn-rich phase in Al-Si-Cu-Mn heat-resistant alloy and its refining effect  

采用E2EM模型预测LaB_(6)相作为Al-Si-Cu-Mn耐热铝合金中初生富Mn相形核基底潜力及其细化效果

作　　者：Guang-jing LI Heng-cheng LIAO 李广敬;廖恒成(东南大学材料科学与工程学院江苏省先进金属材料高技术研究重点实验室,南京211189)

机构地区：[1]Jiangsu Key Laboratory of Advanced Metallic Materials,School of Materials Science and Engineering,Southeast University,Nanjing 211189,China

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第6期1795-1804,共10页中国有色金属学报（英文版）

基　　金：supported by Jiangsu Key Laboratory Metallic Materials, China (No. BM2007204);the Fundamental Research Funds for the Central Universities, China (No. 2242016k40011)。

摘　　要：Edge-to-edge matching(E2EM)model was used to predict the potency of LaB_(6) as the heterogeneous nucleation substrate for primary Al_(13)Mn_(4)Si_(8) phase formed during the solidification of Al−Si−Cu−Mn heat-resistant alloy.There are five pairs of orientation relationships(ORs)between LaB_(6) and Al_(13)Mn_(4)Si_(8) phases which meet the criteria of E2EM model.One pair of plane ORs((110)LaB_(6)//(110)Al_(13)Mn_(4)Si_(8))are demonstrated by TEM observation.This strongly indicates that the LaB_(6) phase can act as the heterogeneous nucleation substrate for the primary Al_(13)Mn_(4)Si_(8) phase.1.0 wt.%of Al−2La−1B master alloy was also added into Al−12Si−4Cu−2Mn alloy to evaluate the refining effect by microstructure observation and tensile test.Experimental results show that addition of Al−2La−1B master alloy can significantly refine the primary Al_(13)Mn_(4)Si_(8) phase,supporting the prediction accuracy of E2EM model.However,such refinement of primary Al_(13)Mn_(4)Si_(8) phase does not lead to an improvement in strength.This is due to the larger difference in elastic modulus between the finally formed Al_(13)Mn_(4)Si_(8) phase and aluminum matrix than that of Al_(15)Mn_(3)Si_(2) phase.通过E2EM模型预测LaB_(6)相作为Al−Si−Cu−Mn耐热铝合金在凝固过程中出现的初生Al_(13)Mn_(4)Si_(8)相异质形核基底的潜力。LaB_(6)相和Al_(13)Mn_(4)Si_(8)相间共有5对位向关系满足E2EM模型的判定标准,其中一对晶面关系((110)LaB_(6)//(110)Al_(13)Mn_(4)Si_(8))被TEM观察证实。这表明LaB_(6)相可作为Al_(13)Mn_(4)Si_(8)相的有效异质形核基底。将1.0%(质量分数)的Al−2La−1B中间合金添加到Al−12Si−4Cu−2Mn合金中,并通过组织观察和力学性能测试来评价细化效果。实验结果表明,添加Al−2La−1B中间合金能显著细化初生Al_(13)Mn_(4)Si_(8)相,证实E2EM模型预测的结果。但初生Al_(13)Mn_(4)Si_(8)相的细化并没有提高合金的强度,这是由于铝基体与初生Al_(13)Mn_(4)Si_(8)相之间的弹性模量差大于Al_(15)Mn_(3)Si_(2)相。

关 键 词：edge-to-edge model Al_(13)Mn_(4)Si_(8)phase LaB_(6)phase heat-resistant aluminum alloy microstructure mechanical property 

分 类 号：TG146.21[一般工业技术—材料科学与工程]