适合于空间技术领域应用的Sn掺杂Mn_3GaN负热膨胀材料研究（英文）

采用球磨后放电等离子体烧结的方法制了化学成分为Mn3Ga1-xSnxN(x=0,0.1,0.2,0.3,0.4)的反钙钛矿锰氮化合物。研究了其热膨胀性能、导热性能和力学性能。结果表明:所有样品热膨胀性能与Sn含量有关,随着Sn含量的增加,负热膨胀温区向高温移动。其中,Mn3Ga0.9Sn0.1N化合物在279到338 K温区内的负热膨胀系数为–27.5×10-6 K-1,负热膨胀温区宽度为59 K。而Mn3Ga0.6Sn0.4N在363~400K温区内的热膨胀系数较小,接近零膨胀。此外,这类负热膨胀材料的热导率约为3.2 W·(m·K)-1,压缩强度约为210 MPa。     

Sn-Doped Mn3GaN Negative Thermal Expansion Material for Space Applications

采用球磨后放电等离子体烧结的方法制了化学成分为Mn3Ga1-xSnxN(x=0,0.1,0.2,0.3,0.4)的反钙钛矿锰氮化合物。研究了其热膨胀性能、导热性能和力学性能。结果表明:所有样品热膨胀性能与Sn含量有关,随着Sn含量的增加,负热膨胀温区向高温移动。其中,Mn3Ga0.9Sn0.1N化合物在279到338 K温区内的负热膨胀系数为–27.5×10-6 K-1,负热膨胀温区宽度为59 K。而Mn3Ga0.6Sn0.4N在363~400K温区内的热膨胀系数较小,接近零膨胀。此外,这类负热膨胀材料的热导率约为3.2 W·(m·K)-1,压缩强度约为210 MPa。     

Mn3（Cu1-xGex）N的负热膨胀现象

在氮气保护下于1073 K用同相烧结法制备了Mna(Cu1-xGex)N化合物.XRD分析表明,这类化合物具有Mn3CuN型反钙钛矿相结构.采用激光干涉法测量了Mn3(Cu1-xGex)N化合物的线膨胀系数.结果表明,当Ge含量为0.40≤x≤0.60时,Mn3(Cu1-xGex)N在一定温度范围内出现负热膨胀现象;随Ge含量的增加,发生负热膨胀的温度升高且温区变宽,而负热膨胀性能减弱.当x=0.60时,发生负热膨胀的温度范围为250-290 K(273 K附近),线膨胀系数为65×10-6 K-1,具备应用潜力.热磁曲线表明,Mn3(Cu1-xGex)N化合物的负热膨胀现象发生在反铁磁性逐渐向顺磁性转变的过程中,由磁有序逐渐消失,自发磁化强度减小所引起的磁容积效应造成的.     

机械超材料研究进展

机械超材料因其具有与直觉相悖的力学性能而受到学者的广泛关注。其独特新颖的性能与自身结构紧密相关,通过设计和制备不同的结构,能够使材料具有许多独特的力学性能。目前,制备工艺的发展和进步使得制备具有任意复杂微米或纳米结构的材料成为现实。本文综述了机械超材料领域中较为常见的几种性能：轻质超强、负泊松比、负可压缩性、负热膨胀性和超流体的研究进展,总结了机械超材料发展的限制因素,并对该领域的发展方向及研究重点进行了展望。     

NEGATIVE THERMAL EXPANSION PHENOMENA\par OF Mn3(Cu1-xGexN

在氮气保护下于1073 K用固相烧结法制备了Mn₃(Cu_1-xGe_x)N化合物. XRD分析表明, 这类化合物具有Mn₃CuN型反钙钛矿相结构. 采用激光干涉法测量了Mn₃(Cu_1-xGe_x)N化合物的线膨胀系数. 结果表明, 当Ge含量为0.40≦x≦0.60时, Mn₃(Cu_1-xGe_x)N在一定温度范围内出现负热膨胀现象; 随Ge含量的增加, 发生负热膨胀的温度升高且温区变宽, 而负热膨胀性能减弱. 当x=0.60时,发生负热膨胀的温度范围为250-290 K(273 K附近), 线膨胀系数为-65×10^-6 K^-1, 具备应用潜力. 热磁曲线表明, Mn₃(Cu_1-xGe_x)N化合物的负热膨胀现象发生在反铁磁性逐渐向顺磁性转变的过程中,由磁有序逐渐消失、自发磁化强度减小所引起的磁容积效应造成的.     

反钙钛矿结构Mn_3Ga_(0.503)Ge_(0.497)N金属化合物的性能

采用氮气保护气氛下固相烧结法制备出Mn_3Ga_(0.503)Ge_(0.497)N化合物,并对其性能进行了测试。通过多晶粉末X射线衍射进行了结构表征和热膨胀性能测试,结果表明:具有立方反钙钛矿结构的Mn_3Ga_(0.503)Ge_(0.497)N化合物在420~470 K温度范围内表现出负热膨胀性能,其平均热膨胀系数为-13.3×10~(-6)K~(-1)。磁性测试结果表明:Mn_3Ga_(0.503)Ge_(0.497)N化合物在457 K左右发生了顺磁-铁磁的磁性转变。力学性能测试结果表明:其维氏硬度范围为450~480 HV,抗压强度和压缩弹性模量分别为350 MPa和2.48 GPa,是一种高硬度脆性陶瓷材料,可以用来制造具有轻质、刚性、低膨胀和高加工性的器件。     

SOEC阴极材料Sr_2FeMoO_(6-δ)的微观结构和性能

选用双钙钛矿结构Sr_2FeMoO6-δ作为固体氧化物电解池的阴极材料,经过压制成型和烧结制备成阴极。利用阿基米德法测定了阴极的孔隙率,结合扫描电子显微镜研究造孔剂的用量对阴极孔隙结构的影响。利用热分析仪测定了不同孔隙结构的阴极受热后热膨胀情况和热膨胀系数,研究其与电解质的热膨胀系数匹配情况。最后利用电化学工作站测试了阴极材料的电化学性能。实验结果表明,双钙钛矿结构Sr2Fe Mo O6-δ有较好地电化学性能以及与电解质LSGM热膨胀系数匹配,有望成为固体氧化物电解池阴极的理想候选材料。     

钙钛矿结构固体氧化物燃料电池阳极材料研究

钙钛矿型氧化物(ABO3)由于其混合导电能力及其在高温氧化还原气氛下具有较好电催化活性和化学稳定性,而且对硫、碳、氧具有良好的容耐性,因此被广泛应用于作为固体氧化物燃料电池的阳极材料.概述了阳极材料的特点及钙钛矿结构的阳极材料的进展情况,对钙钛矿结构的阳极材料的制备方法及性能进行了总结.     

负热膨胀材料ZrW2O8研究现状

ZrW2O8是由0.3 K至分解温度1050 K都具有各向同性的负热膨胀化合物,但由于其窄的热稳定范围反应合成相当困难.本文综述了该材料的负热膨胀特性及各种合成制备方法,简单介绍了其潜在的应用.     

石英玻璃热膨胀性能的高温分子动力学研究

采用基于第一性原理的COMPASS力场对石英玻璃的热膨胀性能作了分子动力学研究。结果分析表明Si-O键长与Si-O-Si键角是导致结构随温度变化的主要因素，两者的变化趋势和变化速率决定了材料热膨胀的不规则性。此外，还根据四面体体积随温度的变化粗略估算了四面体间隙的变化，对负热膨胀现象做了进一步讨论。     

Recent advances in pseudocapacitor electrode materials: Transition metal oxides and nitrides

Faraday pseudocapacitors take both advantages of secondary battery with high energy density and supercapacitors with high power density, and electrode material is the key to determine the performance of Faraday pseudocapacitors. Transition metal oxides and nitrides, as the two main kinds of pseudocapacitor electrode materials, can enhance energy density while maintaining high power capability. Recent advances in designing nanostructured architectures and preparing composites with high specific surface areas based on transition metal oxides and nitrides, including ruthenium oxides, nickel oxides, manganese oxides, vanadium oxides, cobalt oxides, iridium oxides, titanium nitrides, vanadium nitrides, molybdenum nitrides and niobium nitrides, are addressed, which would provide important significances for deep researches on pseudocapacitor electrode materials.     

Mechanical alloying and severe plastic deformation of nanocrystalline high-nitrogen stainless steels

High-nitrogen, nickel-free nanocrystalline stainless steels with Fe-(18?C20)Cr-1N and Fe-(23?C25)Cr-(10?C11)Mn-1N (wt %) compositions were obtained by mechanical alloying (MA) in a high-energy planetary ball mill in an argon atmosphere. As a source of nitrogen, we used chromium and manganese nitrides that enter the composition of the powder mixture with pure metal components. Comparative studies of the evolution of the structure during MA using X-ray diffraction, M?ssbauer spectroscopy, and transmission and scanning electron microscopy have demonstrated that, in an Fe-Cr-N system, a ferrite bcc structure is preserved for up to 120 h of MA. In an Fe-Cr-Mn-N system, where nitrogen was supplied by chromium nitrides, complete austenization occurred after 60 h of the MA. The maximum acceleration of the formation kinetics of a high-nitrogen austenite was obtained in an Fe-Cr-Mn-N system, where nitrogen was obtained from a manganese nitride. The mechanisms of solid-phase reactions in powder mixtures during MA are discussed under both the deformation-induced dissolution of nitrides in a metallic matrix and the stability of a nitrogen-supersaturated ferrite with respect to ?? ?? ?? transformation.     

射频磁控溅射ZrW2O8薄膜的高温退火研究

采用ZrW2O8陶瓷靶材,以射频磁控溅射法在不同基片上沉积制备ZrW2O8薄膜.利用X射线衍射(XRD)仪和扫描电子显微镜(SEM)研究靶材性能和退火温度、气氛以及基片对薄膜的相组成、表面形貌的影响.结果表明:ZrW2O8靶材具有较高的纯度和致密度,磁控溅射制备的薄膜为非晶态,在730℃左右通氧条件下退火后得到择优生长的ZrW2O8薄膜:在750℃左右退火得到三方相ZrW2O8薄膜;在1200℃密闭的条件下淬火得到立方相ZrW2O8薄膜;在15到700℃温度区间内,制备的立方相ZrW2O8薄膜负热膨胀系数为-14.47×10-6 K-1,随着退火温度的提高,薄膜出现一些孔洞和裂纹.     

Effect of aluminum on mechanical solid-state alloying of iron with nitrogen in ball mill

M?ssbauer spectroscopy and X-ray diffraction analysis have been used to study mechanical solidstate alloying with nitrogen and chromium of iron and an Fe-3Al alloy in the process of the mechanical activation with chromium nitrides in a ball mill. It is shown that the deformation-induced dissolution of chromium nitrides in iron and Fe-3Al matrices results in the formation of substitutional chromium and interstitial nitrogen solid solutions. The alloying of iron with aluminum accelerates the process of the deformation-induced dissolution of chromium nitrides, but reduces the nitrogen content in the interstitial solid solution. Post-deformation annealing generally leads to the escape of aluminum from the matrix, the substitution of chromium for aluminum, and the formation of fine nitrides AlN.     

Improved Diffusion-Resistant Ability of Multicomponent Nitrides: From Unitary TiN to Senary High-Entropy (TiTaCrZrAlRu)N

Multicomponent high-entropy nitrides have been attempted as robust diffusion barrier materials to inhibit the severe interdiffusion of Cu and Si; however, the improvement in their diffusion resistance relative to the abilities of few-component nitrides has actually not been verified. Thus, in this study, nitride barriers with different numbers of components (metallic elements), from unitary TiN to senary high-entropy (TiTaCrZrAlRu)N (with the same face-centered cubic structure and a thickness of 5 nm), were prepared. The failure of these nitride barriers in resisting the interdiffusion of Cu and Si was examined, and the activation energy of Cu diffusion through the nitrides was determined. With more components incorporated, the failure temperature of the nitrides was found to markedly increase from 550°C to 900°C, and the activation energy of Cu diffusion was effectively raised from 107 kJ/mol to 161 kJ/mol. Severe lattice distortions and random cohesions are suggested as the dominant factors for the improved diffusion-resistant ability of the multicomponent high-entropy nitrides.     

Deformation-induced cyclic phase transitions of dissolution-precipitation of nitrides in surface layers of Fe-Cr-(Ni)-N alloys

Methods of M?ssbauer spectroscopy, transmission electron microscopy, and X-ray diffraction have been used to study structural and phase transformations in surface layers of iron and Fe-Cr-(Ni) alloys subjected to ion-plasma nitriding and subsequent severe cold plastic deformation by shear under pressure in Bridgman anvils. It has been shown that the cyclic phase transformations of dissolution-precipitation of nitrides in the alloys result in the formation of nitrogen-supersaturated solid solutions, precipitation of secondary nitrides, and the nanostructurization of the metallic matrix. It has been established that the introduction of chromium into iron alloys accelerates the formation of nitrides upon nitriding and makes it possible to obtain solid solutions strongly supersaturated with nitrogen (more than 10 at % N in the fcc lattice) during subsequent deformation.     

Deformation-Induced Dissolution and Precipitation of Nitrides in Austenite and Ferrite of a High-Nitrogen Stainless Steel

Methods of Mössbauer spectroscopy and electron microscopy have been used to study the effect of the severe plastic deformation by high pressure torsion in Bridgman anvils on the dissolution and precipitation of chromium nitrides in the austenitic and ferritic structure of an Fe_71.2Cr_22.7Mn_1.3N_4.8 high-nitrogen steel. It has been found that an alternative process of dynamic aging with the formation of secondary nitrides affects the kinetics of the dissolution of chromium nitrides. The dynamic aging of ferrite is activated with an increase in the deformation temperature from 80 to 573 K.     

国产轧制高锰钢板在抛丸设备上的应用

国产轧制高锰钢板近几年有了较好的发展,在机械性能方面有了明显的提高,基本接近进口优质高锰钢板的水平。介绍了国产轧制高锰板在抛丸机上应用,通过在各类抛丸机上的应用实践证明国产轧制钢板可以替代进口高锰钢板在抛丸机上的使用,并且可以降低维修工作量,节约使用成本,为抛丸机关键部位的国产化提供可能。     

RELATIONSHIP OF LENNARD－JONES POTENTIAL ANDMORSE POTENTIAL WITH W＿x（r） POTENTIAL

ＲＥＬＡＴＩＯＮＳＨＩＰＯＦＬＥＮＮＡＲＤ－ＪＯＮＥＳＰＯＴＥＮＴＩＡＬＡＮＤＭＯＲＳＥＰＯＴＥＮＴＩＡＬＷＩＴＨＷ＿ｘ（ｒ）ＰＯＴＥＮＴＩＡＬＸｉｅ，Ｙｏｕｑｉｎｇ（ＤｅｐａｒｔｅｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｉｎ...     

增材制造高熵合金复合材料综述（英文）

高熵合金复合材料是一种由高熵合金基体和第二相(如碳化物、硼化物、氮化物)组成的新型金属基复合材料。近年来，高熵合金复合材料的优异性能吸引了大量研究者的关注。然而，在传统铸造高熵合金复合材料中会发生严重的成分偏析，这极大制约了高熵合金复合材料的发展。目前，新兴的3D打印技术可以解决这一问题并制备出复杂形状的零件，因此，得到了研究者的关注并有大量相关文献报导。本文总结了截止目前3D打印高熵合金复合材料的研究进展。首先，对高熵合金及其复合材料做了介绍，并总结了目前高熵合金复合材料粉末的制备方法(气雾化法和机械合金化法)。其次，介绍了几种常用于成形高熵合金复合材料的3D打印方法(粉末床熔化法和直接金属沉积技术)，并对其相应的微观结构进行了分析。然后，对比了3D打印高熵合金复合材料、3D打印高熵合金及其铸件的力学性能，并对其硬度抗磨损、腐蚀和氧化性能进行了探讨。最后，对3D打印高熵合金复合材料的发展前景进行了展望。