Electronic structure of Ag-Cu alloys

Ｉｎｏｒｄｅｒｔｏａｄｖａｎｃｅｍａｔｅｒｉａｌｓｓｃｉｅｎｃｅｉｎｔｏａｓｙｓｔｅｍａｔｉｃｓｃｉｅｎｃｅｏｆｍａｔｅｒｉａｌｓａｎｄｅｍｐｉｒｉｃａｌｄｅｓｉｇｎｏｆｍａｔｅｒｉａｌｓｉｎｔｏａｓｃｉｅｎｔｉｆｉｃｄｅｓｉｇｎｏｆｍａｔｅｒｉａｌｓ,ｗｅｆｉｒｓｔｅｓｔａｂｌｉｓｈｅｄｔｈｅｏｎｅａｔｏｍｔｈｅｏｒｙｏｆｐｕｒｅｍｅｔａｌｓ(ｓｉｍｐｌｙＯＡｔｈｅｏｒｙ)[1—6]ａｎｄｔｈｅｎｄｅｖｅｌｏｐｅｄｔｈｅｃｅｎｔｒａｌａｔｏｍｓｍｏｄｅｌｉｎｔｈｅｓｔａｔｉｓｔｉｃｔｈｅｒｍｏｄｙｎ…     

Atomic energies and Gibbs energy functions of Ag-Cu alloys

1　ＳｙｓｔｅｍａｔｉｃｓｃｉｅｎｃｅｏｆｍａｔｅｒｉａｌｓＡｍｅｔａｌｌｉｃｍａｔｅｒｉａｌｉｓａｃｏｍｐｌｅｘｓｙｓｔｅｍｃｏｎｓｉｓｔｉｎｇｏｆｏｒｇａｎｉｚａｔｉｏｎ,ｐｈａｓｅａｎｄａｔｏｍｓａｔｄｉｆｆｅｒｅｎｔｌｅｖｅｌｓ.“Ｅｎｅｒｇｙ”ａｎｄ“ｆｏｒｍ”ａｒｅｔｈｅｂａｓｉｃｐｒｏｐｅｒｔｉｅｓｏｆｍａｔｅｒｉａｌｓ.Ｆｒｏｍｔｈｅｖｉｅｗｐｏｉｎｔｏｆｅｎｅｒｇｙｔｈｅｓｔｕｄｉｅｓｏｎｔｈｅｓｔｒｕｃｔｕｒｅｓｏｆｍｅｔａｌｌｉｃｍａｔｅｒｉａｌｓｃａｎｂｅｍａｄｅａｔｔｈｒｅ…     

Phase diagram structure model of glass

Phase diagram structure model of glass has been proposed and discussed. Validity of this model has been supported by lots of experimental data in various glass systems.     

Atomic volumes and volume functions for Ag-Cu alloys

Ｔｈｅｔａｓｋｏｆａｌｌｏｙｄｅｓｉｇｎｉｓｔｏｐｒｏｄｕｃｅａｌｌｏｙｓｗｉｔｈｅｘｐｅｃｔｅｄｐｒｏｐｅｒｔｉｅｓｂｙｃｈｏｏｓｉｎｇｅｌｅｍｅｎｔｓａｎｄｔｈｅｉｒａｐｐｒｏｐｒｉａｔｅｐｒｏｐｏｒｔｉｏｎｓａｎｄａｄｏｐｔｉｎｇｒｅａｓｏｎａｂｌｅｗｏｒｋｉｎｇｌｉｎｅ,ｏｒｉｎｖｅｒｓｅｌｙ,ｔｏｐｒｅｄｉｃｔｐｒｏｐｅｒｔｉｅｓｏｆａｌｌｏｙｓａｃｃｏｒｄｉｎｇｔｏｔｈｅｅｌｅｍｅｎｔｓ,ｔｈｅｉｒｐｒｏｐｏｒｔｉｏｎｓａｎｄｓｔｒｕｃｔｕｒｅｓ.Ｔｈｅｓｅｔｗｏｉｎｖｅｒｓｅｐｒｏｃｅ…     

Magnetic properties and XPS of Dy-Y and Dy-Nd alloys

The magnetic properties and X-ray photoelectron spectroscopy (XPS) spectra in the Dy100-xYx and Dy100-zNdz rare-earth alloys are studied.The magnetism measurements show that the dhcp crystal-field influence in the Dy-Nd alloys,which tends to destroy the orbital moment,does not vanish even though a field of 6T is applied.With increasing Y (or Nd) content the temperature region corresponding to helical phase becomes wider (or narrower).The XPS records suggest that the property of the valence fluctuation in neodymium tends to increase the Fermi wave vector kF of the Dy-Nd alloys.This testifies that the abrupt dropping of the Neel temperature,as Nd is introduced,is not only due to a dilution effect of Nd.The introduction of light rare earths into heavy ones is favorable for suppressing the helical phase in the alloys and overcoming the negative magnetocaloric effect.This result will play a guiding role in designing composite magnetic refrigeration working substances.     

Thermodynamic properties and mixing thermodynamic parameters of two-phase metallic melts

Based on the calculating model of metallic melts involving eutectic, the calculating equations of mixing thermodynamic parameters for two phase metallic melts have been formulated in the light of those equations of homogeneous solutions. Irrespective as to whether the activity deviation relative to Raoultian behavior is positive or negative, or the deviation is symmetrical or unsymmetrical, the evaluated results not only agree well with experimental values, but also strictly obey the mass action law. This testifies that these equations can authentically reflect the structural reality and mixing thermodynamic characteristics of two-phase metallic melts. The calculating equations of mixing thermodynamic parameters for the model of two phase metallic melts offer two practical criteria (activity and mixing thermodynamic parameters) and one theoretical criterion (the mass action law).     

Phase transformation behaviors and shape memory effects of TiNiFeAl shape memory alloys

Measurements of electrical resistivity, X-ray diffraction, and tensile test at room temperature and ?196°C were performed to investigate the effects of Al addition substituting Ni on the phase transformation behaviors, the mechanical properties, and the shape memory effects of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys. It is found that 1at% Al addition dramatically decreases the martensitic start transformation temperature and expands the transformation temperature range of R-phase for TiNiFeAl alloys. The results of tensile test indicate that 1at% Al improves the yield strength of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys by 40% and 64%, but de- creases the plasticity to 11% and 12% from 26% and 27% respectively. Moreover, excellent shape memory effect of 6.6% and 7.5% were found in Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys, which results from the stress-induced martensite transformation from the R-phase.     

Microstructure and mechanical properties of Al_3Ti-based alloys in Al-Ti-Mo-X quaternary systems

A part of Al-Ti-Mo-Cr quaternary phase diagram is constructed for the microstructure control of D022-Al3Ti or its derivative, L12-(Al,Cr)3Ti, -based alloys. It was found that quaternary bcc phase equilibrates with either D022-Al3Ti or L12-(Al,Cr)3Ti, or both, exist in large compositional areas. The mechanical properties is strongly affected by precipitates appearing, and presumably alloy microstructures.     

Effect of HIPing time on the properties of TiAl alloys

The compacted TiAl alloys were prepared and the effects of HIPing time on their properties were studied. At 1100 ℃, 80 Mpa, the density of TiAl alloy reached up to 3.46 g/cm3 after 10 min HIPing. The densities of TiAl alloys did not significantly increase with the time increasing from 10 min to 70 min. Under the experimental conditions, the TiAl alloys obtained is an unstable state alloy, and the effect of HIPing time on the TiAl phase is not significant. The micro-cracks appear in inner of TiAl alloy with the HIPing time increase. At 1380 ℃, after one hour heat treatment, the micro-cracks disappear and the phase changes into stable state and its microstructure changs into lamella.     

Behavior of oxygen in DG? invar-Cu alloys and its effects on mechanical and physical properties

The invar alloy powder, mixed with different Cu powder contained different content of oxygen, was compacted and sintered into four sorts of DG™ invar-Cu low expansion and high conductivity alloy specimens. The mechanical and physical properties of the alloys were tested and analyzed. The behavior of oxygen and its effect mechanism were discussed. The results show that the ultimate strength decreases with the increase of oxygen content, so does the coefficient of thermal expansion (α) whereas the α platform is shortened. Project supported by the Natural Science Foundation of Hunan Province Synopsis of the first author Wang Zhifa, Senior Engineer, born in 1946, specializing in electronic packing materials. His studied group developed the first W disc and the first invar-Cu plate of the country for power semiconductor devices.     

EuCl3-PrCl3二元系相图的研究

利用DTA测定了EuCl3-PrCl3二元系相图,发现该体系有一个异份熔化化合物EuCl3·2PrCl3,转熔点为573 ℃,EuCl358.8%(摩尔分数);低共熔点为510 ℃,EuCl375.6%(摩尔分数).同时探讨了相图的某些规律.     

Phase Equilibria in Ni Rich Region of Ni-Al-Fe System

The phase equilibria between γ, α, γ' and β in the Ni-rich region of the Ni-Al-Fe system were investigated by the diffusion couple method and thermodynamic models. The thermodynamic parameters were assessed based on experimental results and thermodynamic data. Moreover, the system's phase equilibria from 900 to 1 300℃ were calculated with regular solution and sublattice models, and it is shown that the theoretic results agree well with experimental phase diagram data.     

Phase diagram of the Fe-rich portion of R-Fe-Al pseudoternary system(R=Dy_(0.65)Tb_(0.25)Pr_(0.1))

The 1000℃ isothermal section of the Fe-rich portion of R-Fe-Al(R=Dy0.65Tb0.25Pr0.1) pseudoternary system has been investigated using optical microscopy,X-ray diffraction,EPMA and DTA techniques.The 1000℃ isothermal section consists of 9 single-phase regions,14 two-phase regions and 6 three-phase regions.In the R-Fe pseudobinary system,except the R2Fe17 compound,the homogeneity regions of other compounds are shifted towards the stoichiometric rare earth-rich side.With Fe partially substituted by Al,the homogeneity region of R(Fe1-xAlx)2 is shifted back to the stoichiometric composition when x=0.15 and remains little changed with 0.15≤x≤0.30.The homogeneity regions of R(Fe1-xAlx)3 and R6(Fe1-xAlx)23 are slightly shifted to the stoichiometric rare earth-rich side with increasing Al content.A vertical section along R=33.33 atomic percentage is also investigated.It consists of 2 single-phase regions,4 two-phase regions and 2 three-phase regions.     

一种核级316LN钢的相图计算与微合金化设计

用热力学方法计算了一种核级316LN钢及其在Nb、V微合金化条件下的伪二元平衡相图,研究了不同温度下钢的平衡相组成。结果表明,316LN钢中的主要析出相为Cr2N、M23C6、和相,Nb微合金化316LN钢中会形成含C的MX,有望提高材料的力学性能和耐晶间应力腐蚀性能,V微合金化316LN钢中会形成VN,但对稳定C的作用不大。     

碱金属卤化物的热力学性质的研究

本文用国产RD496—L型微热量热计测定了25℃时NaCl,KCl,RbCl,csCl系列在水中的溶解热,用Nriss—Cobble方法外推得到四种的标准溶解热,并与文献值进行了比较。对这四种盐在水溶液中的热力学行为进行了简单的计论。     

Effect of the repeated melting of mother ingot on the stability of icosahedral phase precipitated from Zr-Al-Ni-Cu-Ag glass

Since the icosahedral phase (I-phase) was first found in a rapidly solidified Al84Mn16 alloy by Shechtman et al.[1] in 1984, a lot of studies on I-phase have been carried out. The typical systems in which the icosahedral quasicrystals can be formed include Al-[2,3], Pd-[4] and Ti-based[5] ones. In most cases, the I-phase forms as metastable phase and its formation depends on the cooling rate. Later, precipitation of I-phase during the crystallization of Zr-based metallic glass was reported…