高强铝合金中间相Al2Cu,Al2CuMg和MgZn2性能的第一性原理计算

廖飞; 范世通; 邓运来; 张劲

doi:10.11868/j.issn.1005-5053.2016.6.001

高强铝合金中间相Al₂Cu,Al₂CuMg和MgZn₂性能的第一性原理计算

doi: 10.11868/j.issn.1005-5053.2016.6.001

廖飞¹,
范世通^1, ,,
邓运来^1,2,
张劲³

1.
中南大学材料科学与工程学院, 长沙 410083
2.
中南大学有色金属材料科学与工程教育部重点实验室, 长沙 410083
3.
中南大学轻合金研究院, 长沙 410083

基金项目:

国家重点基础研究发展计划资助项目 2012CB619505

详细信息

通讯作者:
范世通(1985-),男,博士,主要从事高性能铝合金材料性能研究,(E-mail)fanstone95@163.com

中图分类号: TG146.2
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- 被引次数: 0
出版历程
- 收稿日期: 2015-12-31
- 修回日期: 2016-03-16
- 刊出日期: 2016-12-01

First-principle Calculations of Mechanical Properties of Al₂Cu, Al₂CuMg and MgZn₂ Intermetallics in High Strength Aluminum Alloys

1.
School of Materials Science and Engineering, Central South University, Changsha 410083, China
2.
Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China
3.
Light Alloy Research Institute, Central South University, Changsha 410083, China

摘要

摘要: 采用第一性原理平面波赝势方法，计算Al-Zn-Mg-Cu系高强铝合金主要中间相Al₂Cu，Al₂CuMg和MgZn₂的结合能、形成焓、弹性常数及态密度。计算结果表明：3相结合能按MgZn₂ > Al₂CuMg > Al₂Cu顺序递减；形成焓按MgZn₂ > Al₂Cu > Al₂CuMg顺序递减；Al₂Cu具有很高的弹性模量，同时具有一定的塑性，可以作为合金的强化相；Al₂CuMg是典型的脆性相，并表现出明显的各向异性，容易诱导产生裂纹；MgZn₂具有良好的塑性，同时熔点较低，是合金的主要强化相；3相中均存在离子键的相互作用，提高了结构稳定性；通过适当降低Cu，Mg含量，提高Zn的含量，有利于生成MgZn₂相，进一步提高合金的综合性能。
- 高强铝合金 /
- 中间相 /
- 第一性原理 /
- 力学性能
Abstract: Structural stabilities, mechanical properties and electronic structures of Al₂Cu, Al₂CuMg and MgZn₂ intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (E_coh) decreases in the order MgZn₂ > Al₂CuMg > Al₂Cu, whereas the formation enthalpy (ΔH) decreases in the order MgZn₂ > Al₂Cu > Al₂CuMg. Al₂Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al₂CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn₂ has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al₂Cu, Al₂CuMg and MgZn₂, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn₂ phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.
- high strength aluminum alloy /
- intermetallics /
- first-principles /
- mechanical properties

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图 1 Al₂Cu(a)，Al₂CuMg(b)和MgZn₂(c)的晶胞模型

Figure 1. Unit cells of the phases Al₂Cu(a),Al₂CuMg(b) and MgZn₂ (c)

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图 2 Al₂Cu，Al₂CuMg和MgZn₂相的态密度

Figure 2. Graphs of density of states of Al₂Cu,Al₂CuMg and MgZn₂(dashed lines represent Fermi level)

(a) Al₂Cu; (b) Al₂CuMg; (c) MgZn₂

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图 3 不同Cu含量的Al-Zn-Mg-Cu系高强铝合金力学性能^[29]

Figure 3. Mechanical properties of Al-Zn-Mg-Cu high strength aluminum alloys with different Cu contents

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表 1 Al₂Cu，Al₂CuMg和MgZn₂三相的空间群、晶格参数、结合能及形成焓

Table 1. Space group,lattice parameters a₀,cohesive energy E_coh and formation enthalpy ΔH of the phases Al₂Cu,Al₂CuMg and MgZn₂

Phase	Space group	Lattice parameter/nm		E_coh/(kJ·mol^-1)	ΔH/(kJ·mol^-1)
Phase	Space group	This work	Others	E_coh/(kJ·mol^-1)	ΔH/(kJ·mol^-1)
Al₂Cu	I4/MCM	a=0.6058,c=0.4873	a=0.6067,c=0.4877^[11]a=0.6057,c=0.4824^[12]	-353.181	-15.042
Al₂CuMg	CMCM	a=0.4012,b=0.9293,c=0.7124	a=0.4010,b=0.9250,c=0.7150^[13]a=0.4012,b=0.9265,c=0.7124^[14]	-307.587	-17.568
MgZn₂	P63/MMC	a=0.5208,c=0.8506	a=0.5222,c=0.8568^[15]a=0.5221,c=0.8567^[16]	-132.628	-13.346

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表 2 Al₂Cu，Al₂CuMg和MgZn₂的弹性常数

Table 2. Calculated elastic constants of phases Al₂Cu,Al₂CuMg and MgZn₂，C_ij/GPa

Phase	Source	C₁₁	C₁₂	C₁₃	C₂₂	C₂₃	C₃₃	C₄₄	C₅₅	C₆₆
Al₂Cu	This work	169.25	76.59	56.37	—	—	183.64	31.45	—	45.23
Al₂Cu	Others^[22]	186.18	71.54	79.20	—	—	179.42	29.23	—	47.24
Al₂CuMg	This work	135.32	36.77	64.29	145.45	52.64	129.26	46.58	70.18	35.46
Al₂CuMg	Others^[5]	156.48	33.37	62.61	175.97	17.66	168.76	43.74	93.02	50.72
MgZn₂	This work	110.97	45.33	36.06	—	—	124.86	26.08	—	—
MgZn₂	Others^[23]	107.25	45.45	27.43	—	—	126.40	27.70	—	—

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表 3 Al₂Cu，Al₂CuMg和MgZn₂力学性能参数

Table 3. Calculated parameters of mechanical property of the phases Al₂Cu,Al₂CuMg and MgZn₂

Phase	Modulus/MPa							B/G	C₁₁-C₁₂	ν	A^U
Phase	B_V	B_R	B	G_V	G_R	G	E	B/G	C₁₁-C₁₂	ν	A^U
Al₂Cu	100.09	100.07	100.08	43.82	46.61	45.21	117.88	2.21	92.66	0.30	-0.30
Al₂CuMg	79.71	62.52	71.12	47.53	44.89	46.21	113.96	1.54	98.55	0.23	0.57
MgZn₂	64.63	64.62	64.62	32.29	31.14	31.71	81.77	2.04	65.64	0.29	0.18
Note: B—bulk modulus；G—shear modulus；E—elastic modulus；B/G—modulus' proportion；C₁₁-C₁₂—elastic constants' difference；ν—Poisson's ratio；A^u—universal elastic anisotropy index.

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表 4 Al₂Cu，Al₂CuMg和MgZn₂ 3相的Bader电荷

Table 4. Calculated Bader charge of Al₂Cu,Al₂CuMg and MgZn₂

Phase	Atom	Charge/e	Atomic volume/10^-3nm³
Al₂Cu	Al	2.154	12.585
	Al	2.174	12.704
	Cu	12.672	19.510
Al₂CuMg	Al	2.487	16.152
	Al	2.490	16.174
	Cu	13.502	27.032
	Mg	0.520	7.033
MgZn₂	Mg	0.560	7.613
	Zn	12.783	21.590
	Zn	12.695	21.007

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参考文献(32)

[1]	方华婵, 陈康华, 巢宏, 等. Al-Zn-Mg-Cu系超强铝合金的研究现状与展望[J]. 粉末冶金材料科学与工程, 2009, 14(6): 351-358. http://www.cnki.com.cn/Article/CJFDTOTAL-FMGC200906002.htm FANG H C, CHEN K H, CHAO H, et al. Current research status and prospects of ultra strength Al-Zn-Mg-Cu aluminum alloy[J]. Materials Science and Engineering of Powder Metallurgy, 2009, 14(6): 351-358.) http://www.cnki.com.cn/Article/CJFDTOTAL-FMGC200906002.htm
[2]	王祝堂, 田荣璋. 铝合金及其加工手册[M]. 长沙: 中南工业大学出版社, 2000: 262-264.
[3]	张新明, 邓运来, 张勇. 高强铝合金的发展及其材料的制备加工技术[J]. 金属学报, 2015, 51(3): 257-271. http://www.cnki.com.cn/Article/CJFDTOTAL-JSXB201503001.htm ZHANG X M, DENG Y L, ZHANG Y. Development of high strength aluminum alloys and processing techniques for the materials[J]. Acta Metallurgica Sinica, 2015, 51(3): 257-271.) http://www.cnki.com.cn/Article/CJFDTOTAL-JSXB201503001.htm
[4]	杨修波. Al-Zn-Mg(Cu)合金的热处理､微观结构与性能研究[D]. 长沙: 湖南大学, 2014. YANG X B. Research on microstructures and properties of Al-Zn-Mg (Cu) alloy after different heat treatment[D]. Changsha: Hunan University, 2014.)
[5]	ZHANG J, HUANG Y N, MAO C, et al. Structural, elastic and electronic properties of θ (Al₂Cu) and S (Al₂CuMg) strengthening precipitates in Al-Cu-Mg series alloys: First-principles calculations[J]. Solid State Communications, 2012, 152(23): 2100-2104. doi: 10.1016/j.ssc.2012.09.003
[6]	韩逸, 李炼, 邓桢桢, 等. 热力学计算优化Al-Zn-Mg-Cu合金成分[J]. 中国有色金属学报, 2011, 21(1): 179-184. doi: 10.1016/S1003-6326(11)60696-1 HAN Y, LI L, DENG Z Z, et al. Constituent optimization of Al-Zn-Mg-Cu alloy based on thermodynamic calculation method[J]. The Chinese Journal of Nonferrous Metals, 2011, 21(1): 179-184.) doi: 10.1016/S1003-6326(11)60696-1
[7]	FURTHMÜLLER J, KRESSE G. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set[J]. Physical Review B, 1996, 54(16): 11169-11186. doi: 10.1103/PhysRevB.54.11169
[8]	JOUBERT D, KRESSE G. From ultrasoft pseudopotentials to the projector augmented-wave method[J]. Physical Review B, 1999, 59(3): 1758-1775. doi: 10.1103/PhysRevB.59.1758
[9]	BURKE K, ERNZERHOF M, PERDEW J P. Generalized gradient approximation made simple[J]. Physical Review Letters, 1996, 77(18): 3865-3868. doi: 10.1103/PhysRevLett.77.3865
[10]	PACK J D, MONKHORST H J. Special points for Brillouin-zone integrations[J]. Physical Review B, 1976, 13(12): 5188-5192. doi: 10.1103/PhysRevB.13.5188
[11]	GRIN Y, WAGNER F R, ARMBRVSTER M, et al. CuAl₂ revisited: composition, crystal structure, chemical bonding, compressibility and Raman spectroscopy[J]. Journal of Solid State Chemistry, 2006, 179(6): 1707-1719. doi: 10.1016/j.jssc.2006.03.006
[12]	CHEN H, YANG L, LONG J. First-principles investigation of the elastic, Vickers hardness and thermodynamic properties of Al-Cu intermetallic compounds[J]. Superlattices and Microstructures, 2015, 79(2): 156-165. http://cn.bing.com/academic/profile?id=2088394626&encoded=0&v=paper_preview&mkt=zh-cn
[13]	CALVERT L D, VILLARS P. Pearson's handbook of crystallographic data for intermetallic phases[M]. OH: ASM, Materials Park, 1991.
[14]	HEYING B, HOFFMANN R D, POETTGEN R. Structure refinement of the S-phase precipitate MgCuAl₂[J]. Chem Inform, 2005, 36(33): 491-494.
[15]	YANG J, WANG J L, WU Y M, et al. Extended application of edge-to-edge matching model to HCP/HCP (α-Mg/MgZn₂) system in magnesium alloys[J]. Materials Science and Engineering: A, 2007, 460/461(5): 296-300. http://cn.bing.com/academic/profile?id=1988643461&encoded=0&v=paper_preview&mkt=zh-cn
[16]	KOMURA Y, TOKUNAGA K. Structural studies of stacking variants in Mg-base Friauf-Laves phases[J]. Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry, 1980, 36(7): 1548-1554. doi: 10.1107/S0567740880006565
[17]	刘俊涛, 张永安, 李锡武, 等. Al-9.5 Zn-2.0 Mg-1.7 Cu合金的热力学计算[J]. 航空材料学报, 2013, 33(6): 1-7. http://jam.biam.ac.cn/CN/article/searchArticleResult.do#1 LIU J T, ZHANG Y A, LI X W, et al. Thermodynamic calculation of Al-9.5Zn-2.0Mg-1.7Cu alloy[J]. Journal of Aeronautical Materials, 2013, 33(6): 1-7.) http://jam.biam.ac.cn/CN/article/searchArticleResult.do#1
[18]	HILL R. The elastic behaviour of a crystalline aggregate[J]. Proceedings of the Physical Society A, 1952, 65(5): 349-357. doi: 10.1088/0370-1298/65/5/307
[19]	WATT J P, PESELNICK L. Clarification of the Hashin-Shtrikman bounds on the effective elastic moduli of polycrystals with hexagonal, trigonal, and tetragonal symmetries[J]. Journal of Applied Physics, 1980, 51(3): 1525-1531. doi: 10.1063/1.327804
[20]	WATT J P. Hashin-Shtrikman bounds on the effective elastic moduli of polycrystals with orthorhombic symmetry[J]. Journal of Applied Physics, 1979, 50(10): 6290-6295. doi: 10.1063/1.325768
[21]	BORN M, HUANG K. Dynamical theory of crystal lattices[M]. Oxford: Oxford University Press, 1998.
[22]	ESHELMAN F R, SMITH J F. Single-crystal elastic constants of Al₂Cu[J]. Journal of Applied Physics, 1978, 49(6): 3284-3288. doi: 10.1063/1.325278
[23]	SEIDENKRANZ T, HEGENBARTH E. Single-crystal elastic constants of MgZn₂ in the temperature range from 4.2 to 300 K[J]. Physica Status Solidi A, 1976, 33(1): 205-210. doi: 10.1002/(ISSN)1521-396X
[24]	PUGH S F. XCII. Relations between the elastic moduli and the plastic properties of polycrystalline pure metals[J]. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1954, 45(367): 823-843. doi: 10.1080/14786440808520496
[25]	RANGANATHAN S I, OSTOJA-STARZEWSKI M. Universal elastic anisotropy index[J]. Physical Review Letters, 2008, 101(5): 055504. doi: 10.1103/PhysRevLett.101.055504
[26]	TANG W, SANVILLE E, HENKELMAN G. A grid-based Bader analysis algorithm without lattice bias[J]. Journal of Physics: Condensed Matter, 2009, 21(8): 84204-84211. doi: 10.1088/0953-8984/21/8/084204
[27]	刘晓涛, 崔建忠. Al-Zn-Mg-Cu系超高强铝合金的研究进展[J]. 材料导报, 2005, 19(3): 47-51. http://www.cnki.com.cn/Article/CJFDTOTAL-CLDB200503013.htm LIU X T, CUI J Z. Progress in research on ultra high strength Al-Zn-Mg-Cu alloy[J]. Materials Review, 2005, 19(3): 47-51.) http://www.cnki.com.cn/Article/CJFDTOTAL-CLDB200503013.htm
[28]	LI C M, CHEN Z Q, ZENG S M, et al. Intermetallic phase formation and evolution during homogenization and solution in Al-Zn-Mg-Cu alloys[J]. Science China Technological Sciences, 2013, 56(11): 2827-2838. doi: 10.1007/s11431-013-5356-5
[29]	樊喜刚, 蒋大鸣, 单长智, 等. Cu含量对Al-Zn-Mg-Cu合金的组织性能和断裂行为的影响[J]. 轻合金加工技术, 2006, 34(2): 31-35. http://www.cnki.com.cn/Article/CJFDTOTAL-QHJJ200602010.htm FAN X G, JIANG D M, SHAN C Z, et al. Effect of copper content on the properties and fracture behavior in Al-Zn-Mg-Cu alloys[J]. Light Alloy Fabrication Technology, 2006, 34(2): 31-35.) http://www.cnki.com.cn/Article/CJFDTOTAL-QHJJ200602010.htm
[30]	MARLAUD T, DDESCHAMPS A, BLEY F, et al. Influence of alloy composition and heat treatment on precipitate composition in Al-Zn-Mg-Cu alloys[J]. Acta Materialia, 2010, 58(1): 248-260. doi: 10.1016/j.actamat.2009.09.003
[31]	FANG X, SONG M, LI K, et al. Effects of Cu and Al on the crystal structure and composition of η (MgZn₂) phase in over-aged Al-Zn-Mg-Cu alloys[J]. Journal of Materials Science, 2012, 47(14): 5419-5427. doi: 10.1007/s10853-012-6428-9
[32]	CHEN K, LIU H, ZHANG Z, et al. The improvement of constituent dissolution and mechanical properties of 7055 aluminum alloy by stepped heat treatments[J]. Journal of Materials Processing Technology, 2003, 142(1): 190-196. doi: 10.1016/S0924-0136(03)00597-1