Mg-Cu合金热物性的分子动力学计算
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摘要
采用原子嵌入势对Mg-Cu合金块体进行了分子动力学模拟。研究了不同含量的Cu元素对Mg-Cu合金的热物性和微观结构的影响。基于能量-温度曲线与比热容-温度曲线对熔化温度以及熔化焓进行了研究,结果表明,随着Cu含量的增加,Mg-Cu合金的熔点先减小后增加,其熔化焓先增加后减小;所有合金的密度和比热容均随Cu含量的增加而降低,热导率随Cu含量的增加而增加。表征了Mg-Cu合金在常温下的微观结构,结果表明,Mg-Cu合金中不同原子之间的相互作用更强,有利于α+Mg_2Cu共晶组织的形成,其模拟结果证实了共晶体是影响合金熔化焓以及热导率的一个主要因素。
The Mg-Cu alloys were studied using the molecular dynamics approach with an embedded atom method(EAM). The thermal properties and microstructure of different Mg-Cu alloys were investigated. The melting temperature and enthalpy were studied based on the energy-temperature curve and the C_p-temperature curve. The results showed that, with the growth of Cu content, the melting point of Mg-Cu alloys decreased first and then increased, and the melting enthalpy increased first and then decreased. With the increase of Cu content, the density and specific heat capacity decreased, and the thermal conductivity increased. We simulated the microstructure of Mg-Cu alloy at the room temperature. The results showed that the interaction between different atoms in Mg-Cu alloy was stronger, which was beneficial to the formation of α+Mg_2Cu eutectic structure. The simulation results also confirmed that the α+Mg_2Cu eutectic was a major factor affecting the melting enthalpy and thermal conductivity of the Mg-Cu alloy.
The Mg-Cu alloys were studied using the molecular dynamics approach with an embedded atom method(EAM). The thermal properties and microstructure of different Mg-Cu alloys were investigated. The melting temperature and enthalpy were studied based on the energy-temperature curve and the C_p-temperature curve. The results showed that, with the growth of Cu content, the melting point of Mg-Cu alloys decreased first and then increased, and the melting enthalpy increased first and then decreased. With the increase of Cu content, the density and specific heat capacity decreased, and the thermal conductivity increased. We simulated the microstructure of Mg-Cu alloy at the room temperature. The results showed that the interaction between different atoms in Mg-Cu alloy was stronger, which was beneficial to the formation of α+Mg_2Cu eutectic structure. The simulation results also confirmed that the α+Mg_2Cu eutectic was a major factor affecting the melting enthalpy and thermal conductivity of the Mg-Cu alloy.
引文
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[16]FANG D,SUN Z,LI Y,CHENG X.Preparation,microstructure and thermal properties of MgBi alloys as phase change materials for thermal energy storage[J].Applied Thermal Engineering,2016,92(1):187-193.
[2]程晓敏,李明娅,朱教群,周卫兵,等.太阳能热利用储热材料的研究与应用[J].变频器世界,2014(8):41-49.CHENG Xiaomin,LI Mingya,ZHU Jiaoqun,ZHOU Weibing,et al.Research and application of solar thermal energy storage materials[J].The World of Inverters,2014(8):41-49.
[3]BIRCHENALL C E,RIECHMAN A F.Heat storage in eutectic alloys[J].Metallurgical and Materials Transactions A,1980,11(8):1415-1420.
[4]BLANCO-RODRíGUEZ P,RODRíGUEZ-ASEGUINOLAZA J,RISUE?O E,et al.Thermophysical characterization of Mg-51%Zn eutectic metal alloy:A phase change material for thermal energy storage in direct steam generation applications[J].Energy,2014,75(7):414-420.
[5]RODRíGUEZ-ASEGUINOLAZA J,BLANCO-RODRíGUEZ P,RISUE?O E,et al.Thermodynamic study of the eutectic Mg49-Zn51,alloy used for thermal energy storage[J].Journal of Thermal Analysis&Calorimetry,2014,117(1):93-99.
[6]RISUENO E,FAIK A,RODRíGUEZ-ASEGUINOLAZA J,et al.Mg-Zn-Al eutectic alloys as phase change material for latent heat thermal energy storage[J].Energy Procedia,2015,69:1006-1013.
[7]程晓敏,陶冰梅,万清舟,李翠,李元元.Mg-Cu-Zn相变储热材料充放热特性研究[J].武汉理工大学学报(信息与管理工程版),2014,36(3):332-336.CHENG Xiaomin,TAO Bingmei,WAN Qingzhou,LI Cui,LI Yuanyuan.Heat charge and discharge characteristics of phase change thermal storage of Mg-Cu-Zn[J].Journal of Wuhan University of Technology(Information&Management Engineering),2014,36(3):332-336.
[8]孙正,程晓敏,朱教群,周卫兵,李元元.Mg基高温相变储热共晶合金熔化相变焓的研究[J].功能材料,2017,48(2):2236-2240.SUN Zheng,CHENG Xiaomin,ZHU Jiaoqun,ZHOU Weibing,LIYuanyuan.Latent heat of melting of Mg-based eutectic alloys as high temperature phase change materials for latent heat storage[J].Journal of Functional Materials,2017,48(2):2236-2240.
[9]PLIMPTON S.Computational limits of classical molecular dynamics simulations[J].Computational Materials Science,1995,4(4):361-364.
[10]YANG Meng,XU Jiangang,ZHANG Yunguang.The effect of layer thickness and interfacial defect with steps of copper-nickel multilayer thin film on deformation mechanism[J].Applied Physics,2015(5):25-32.
[11]DAW M S,BASKES M I.Embedded-atom method:Derivation and application to impurities,surfaces,and other defects in metals[J].Physical Review B,1984,29(12):6443-6453.
[12]FOILES S M,BASKES M I,DAW M S.Calculation of the surface segregation of Ni-Cu alloys with the use of the embedded-atom method[J].Physical Review B,1985,32:7685-7693.
[13]冯黛丽,冯妍卉,张欣欣.小尺寸铝纳米团簇的相变行为[J].物理学报,2013,62(8):111-116.FENG Daili,FENG Yanhui,ZHANG Xinxin.Melting and freezing behavior of aluminum nanoclusters with small size[J].Acta Physica sinica,2013,62(8):111-116.
[14]WIRNSBERGER P,FIJAN D,SARIC A,et al.Non-equilibrium simulations of thermally induced electric fields in water[J].The Journal of Chemical Physics,2016,144(22):224102-1-224102-16.
[15]YING T,ZHENG M Y,LI Z T,et al.Thermal conductivity of ascast and as-extruded bnary Mg-Al alloys[J].Journal of Alloys&Compounds,2014,608(38):19-24.
[16]FANG D,SUN Z,LI Y,CHENG X.Preparation,microstructure and thermal properties of MgBi alloys as phase change materials for thermal energy storage[J].Applied Thermal Engineering,2016,92(1):187-193.