The novel low density MgxTiAlFeNiCr (x=0.6~2.0) high-entropy alloys were prepared by mechanical alloying, the relation of Mg content, thermodynamic parameter and phase structure was researched. The results showed that the prepared high-entropy alloy powders were approximately spherical particles with a diameter about 3 μm. The measurements of X-ray diffraction (XRD) and analyses of energy-dispersive X-ray spectrometry (EDS) revealed that Mg had a high solid solubility in BCC (body center cubic) lattice. The results of thermodynamic calculation showed that the alloys (x=0.6~1.4) had a single BCC1 phase when 8.68%≤δ≤9.77% (δ was atomic radii mismatches), 14.78 J/(mol?K)≤ΔSmix≤14.82 J/(mol?K) (ΔSmix was mixing entropy) and –14.13 kJ/mol≤ΔHmix≤–6.76 kJ/mol (ΔHmix was mixing enthalpy). However, the alloys (x=1.6~1.8) consisted of BCC1 and BCC2 phases when 10.0%≤δ≤10.1%, 14.65 J/(mol?K)≤ΔSmix≤14.74 J/(mol?K) and –5.40 kJ/mol≤ΔHmix≤–4.19 kJ/mol. When x≥2.0, Mg content exceeded the solid solubility of Mg in BCC1 and BCC2 lattices. As a result, Mg2.0TiAlFeNiCr alloy contained the main phases BCC1 and BCC2 and the minor phases Mg and intermetallic compound. The lattice constant (a) of BCC1 and BCC2 were determined respectively to be 0.289 and 0.291 nm by the XRD measurement and high resolution transmission electron microscope (HRTEM) analysis. For BCC1 phase, Fe acted as a solvent element whereas Mg, Ti, Al, Ni and Cr behaved like solute elements. For BCC2, however, Cr acted as a solvent element whereas Mg, Ti, Al, Fe and Ni behaved like solute elements. Compared with BCC1, high Mg content was achieved in BCC2 phase. Moreover, BCC1 and BCC2 displayed a semicoherent interface. The MgxTiAlFeNiCr (x=0.6~2.0) high-entropy alloys exhibited a good corrosion resistance in 3.5wt% NaCl solution. But the corrosion resistance decreased with the increasing of Mg in the alloys.
Tingzhi SI Qinghua LIU Wenxiang XU Xiaoli DING
. Phase evolution and corrosion resistance of MgxTiAlFeNiCr (x=0.6~2.0) high-entropy alloys[J]. The Chinese Journal of Process Engineering, 2019
, 19(2)
: 393
-399
.
DOI: 10.12034/j.issn.1009-606X.218204
[1] Yeh J W, Chen SK, Lin SJ, et al.Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes [J]. Adv. Eng. Mater., 2004, 6: 229–303.[J].Advanced Engineering Materials, 2004, 6(5):299-303
[2] Tong CJ, Yeh JW.Mechanical performance of the AlxCoCrCuFeNi high-entropy alloys system with multiprincipal elements [J]. Metall. Mater. Trans. A, 2005, 36: 1263–1271.[J].METALLURGICAL AND MATERIALS TRANSACTIONS A, 2005, 36A(6):1263-1271
[3]Zhang Y, Zuo T T, Tang Z, et al.Microstructures and properties of high-entropy alloys[J].Prog. Mater. Sci., 2014, 61(8):1-93
[4] Murty B S, Yeh J W, Ranganathan S.High Entropy Alloys [M]. Elsevier Inc., London, 2014.
[5]Tsai M H, Yeh J W.High-Entropy Alloys: A Critical Review[J].Mater. Res. Letters, 2014, 2(3):107-123
[6] 张勇.非晶和高熵合金[M]. 科学出版社. 2010: 78–81.
[7] Ding P, Mao A, Zhang X, et al.Preparation, characterization and properties of multicomponent AlCoCrFeNi2. 1 powder by gas atomization method [J]. J. Alloys Comp., 2017, 721: 609–614.[J].JournalofAlloysandCompounds, 2017, 721(8):609-614
[8] 姚陈忠, 张鹏, 李高仁, 等.电化学制备Fe13.8Co28.7Ni4.0Mn22.1Bi14.9Tm16.5高熵合金及其软磁性研究[J]. 中国稀土学报. 2008, 8: 367–369.[J].中国稀土学报, 2008, 26(9):367-369
[9]Youssef K M, Zaddach A J, Niu C, et al.A novel low-density,high-hardness,high-entropy alloy with close-packed single-phase nanocrystalline structures[J].Mater. Res. Letters, 2015, 3(2):95-99
[10] Khanchandani H, Sharma P, Kumar R, et al.Effect of sintering on phase evolution in AlMgFeCuCrNi4.75 high entropy alloy, Adv. Powder Technol., 2016, 27, 289–294.[J].AdvancedPowderTechnology, 2016, 27(10):289-294
[11] Maulik O, Kumar V.Synthesis of AlFeCuCrMgx (x = 0, 0.5, 1, 1.7) alloy powders by mechanical alloying [J]. Mater. Charact., 2015, 110:116–125.[J].MaterialsCharacterization, 2015, 110(2):116-125
[12] 王稳.轻质及含镁高熵合金的设计、微观组织及储氢性能研究[D]. 兰州理工大学, 2014.
[13] Sun W H, Huang X J, Luo Alan A.Phase formations in low density high entropy alloys [J]. CALPHAD, 2017, 56: 19–28.[J].CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry, 2017, 56(7):19-28
[14] Maulik O, Kumar D, Kumar S, et al.Structural evolution of spark plasma sintered AlFeCuCrMgx (x = 0, 0.5, 1, 1.7) high entropy alloy powders [J]. Intermetallics, 2016, 77: 46–56.[J].Intermetallics, 2016, 77(12):46-56
[15] Otto F, Yang Y, Bai H, George E P.Relative effects of enthalpy and entropy on the phase stability of high-entropy alloys [J]. Acta Mater., 2013, 61: 2628–2638.[J].Acta Materialia, 2013, 61(7):2628-2638
[16]Guo S, Liu C T.Phase stability in high entropy alloys: formation of solid solution phase and amorphous phase[J].Prog. Nat. Sci.: Mater. Int., 2015, 211(21):433-446
[17] Yang X, Zhang Y.Prediction of high-entropy stabilized solid solution in multi-component alloys [J]. Mater. Chem. Phys., 2012, 132: 233–238.[J].Materials Chemistry & Physics, 2012, 132(2-3):233-238
[18]Takeuchi A, Inoue A.Classification of bulk metallic glasses by atomic size difference,heat of mixing and period of constituent elements and its application to characterization of the main alloying element[J].Mater. Trans., 2005, 46(12):2817-2829
[19] Miracle D B, Senkov O N.Acritical review of high entropy alloys and related concepts. Acta Mater., 2017, 122: 448–511.[J].Acta Materialia, 2016, 122(8):448-511
[20]张青来, 钱阳, 安志斌, 等.基于激光冲击的镁合金在溶液中电化学腐蚀的研究[J].中国激光, 2014, 41(9):76-82
