Holographic alloy positioning design system and holographic network phase diagrams of Au-Cu system

Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is to establish holographic alloy positioning design (HAPD) system, of which the base consists of measurement and calculation center, SMMS center, AGE center, HAPD information center and HAPD cybernation center; Second, the resonance activating-sychro alternating mechanism of atom movement may be divided into the located and oriented diffuse modes; Third, the equilibrium and subequilibrium holographic network phase diagrams are blueprints and operable platform for researchers to discover, design, manufacture and deploy advanced alloys, which are obtained respectively by the equilibrium lever numerical method and cross point numerical method of isothermal Gibbs energy curves. As clicking each network point, the holographic information of three structure levels for the designed alloy may be readily obtained: the phase constitution and fraction, phase arranging structure and properties of organization; the composition, alloy gene arranging structure and properties of each phase and the electronic structures and properties of alloy genes. It will create a new era for network designing advanced alloys.

Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of AuCu_3-type sublattice system

Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.

Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of Au_3Cu-type sublattice system

Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.

Towards high strength cast Mg-RE based alloys:Phase diagrams and strengthening mechanisms

Mg-rare earth(RE)based systems provide several important commercial alloys and many alloy development opportunities for high strength applications,especially in aerospace and defense industries.The phase diagrams,microstructure,and strengthening mechanisms of these multicomponent systems are very complex and often not well understood in literature.We have calculated phase diagrams of important binary,ternary,and multicomponent RE-containing alloy systems,using CALPHAD(CALculation of PHAse Diagrams).Based on these phase diagrams,this paper offers a critical overview on phase equilibria and strengthening mechanisms in these alloy systems,including precipitation,long period stacking order(LPSO),and other intermetallic phases.This review also summarized several promising Mg-RE based cast alloys in comparison with commercial WE54 and WE43 alloys;and explored new strategies for future alloy development for high strength applications.It is pointed out that the combination of precipitation and LPSO phases can lead to superior strength and ductility in Mg-RE based cast alloys.The precipitates and LPSO phases can form a complex three-dimensional network that effectively impedes dislocation motion on the basal and non-basal planes.The LPSO phases can also prevent the coarsening of precipitates when they interact,thus providing good thermal stability at elevated temperatures.Future research is needed to determine how the combination of these two types of phases can be used in alloy design and industrial scale applications.

Relationship between the types of binary alloy phase diagrams of Ⅷ and IB group elements and the Mendeleev numbers

The relationship between the types of binary alloy phase diagramsof VIII and Ib group elements and the Men- deleev numbers wasdiscussed for the first time using the VIII and IB group elements assolvent metals (A) and the other elements as solute metals (B),basesd on their alloy phase diagram types. The Mendeleev numbers ofthe solvent metals and the solute metals were expressed as M_A andM_B, respectively. A two-dimension map of M_A/M_B was drawn. It isindi- cated that there is an oblique line in the map, which dividesthe binary alloy phase diagram types of solvent metals into twosymmetry parts, the phase diagram types of the other elements withsolvent metals located at the above or down of the line respectively,while on the line, △M = 0.

Determination of High Pressure Phase Diagrams of the Ternary Alloy System

everal vertical sections of the phase diagram of Cd-Sn-Zn system with a constant mole fraction X_(cd)=0.2 were determined by means of differential thermal anal- ysis(DTA)at high pres:ures 0.0,0.5,1.5,and 2. 0 GPa respectively. The eutectic temperature of the system increases by about 50K from atmospheric pressure to the high pressure 2.0 GPa,but the ternary eutectic composition changes slightly with the pressure chnge.

Phase transformation of Al-Zn (Cu) alloys and the phase diagram of Al-Zn-Cu system

The room temperature phase diagram of Al-Zn-Cu system is the important basis for judging the phase constituents of the materials at the usage condition. New results about the room temperature phase diagram of the low copper side in the Al-Zn-Cu systems have been shown in this study. Miscibility gap of fcc phase in the Al-Zn-Cu system has also been studied by experimental diffusion-couple method and thermodynamic calculation. Properties of this miscibility gap have been known. It is practically significant for the study on the aging behavior and for the control of the microstructure and properties of the Al alloys with Zn and Cu element.

Establishment of continuous cooling transformation diagrams of aluminum alloys using in situ voltage measurement

An effective method was proposed to establish the continuous cooling transformation（CCT） diagrams of aluminum alloys using in situ voltage measurement.The voltage change of samples with predefined dimension was recorded under the constant current state during continuous cooling.Solutionizing time,together with starting and finishing temperatures of phase transformation of the alloy can be obtained from relationships of voltage vs time and temperature.A critical cooling rate without detectable phase transition during continuous cooling can be determined.Continuous cooling transformation diagrams of tested samples can be established conveniently based on these results.Microstructure observation and differential scanning calorimetry（DSC） testing were applied to verify the reliability of continuous cooling transformation diagram.

Thermodynamic modelling and applications of Ce-La-O phase diagram

The Ce-La-O system was investigated via experiments and thermodynamic modeling. A series of CeO2-LaO1.5 mixtures were prepared by co-precipitation technique and examined by X-ray diffraction. Mutual solubilities between LaO1.5 and CeO2 at 1273 K were determined. Using the new experimental data together with literature information, a set of self-consistent thermodynamic parameters for the CeO2-LaO1.5 system were optimized. Combined with thermodynamic descriptions of Ce-O and La-O systems from literature, several property diagrams of Ce-La-O system were calculated and used to explain oxidation process of the Ce-La alloys. The fluorite phase is the unique oxidation products for most of the Ce-La alloys.

Thermodynamic database of the phase diagrams in the Mg-Al-Zn-Y-Ce system

The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design Mg alloys using the calculation of phase diagrams （CALPHAD） method, where the Gibbs energies of solution phases such as liquid, fcc, bcc, and hcp phases were described by the subregular solution model, whereas those of all the compounds were described by the sublattice model. The thermodynamic parameters describing Gibbs energies of the different phases in this database were evaluated by fitting the experimental data for phase equilibria and thermodynamic properties. On the basis of this database, a lot of information concerning stable and metastable phase equilibria of isothermal and vertical sections, molar fractions of constituent phases, the liquidus projection, etc., can be predicted. This database is expected to play an important role in the design of Mg alloys.

Vertical section phase diagrams of La−Fe−B ternary system

The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium alloys,together with their heat flow−temperature curves,phase diagrams for three vertical sections were drawn:La_(x)Fe_(82)B_(y)(x+y=18),La_(x)Fe_(70)B_(y)(x+y=30)and La_(x)Fe_(53)B_(y)(x+y=47),where x and y represent mass fraction of La and B,respectively,%.Additionally,according to the phase diagrams,the compound La2Fe14B was identified as a stable phase at high temperatures.It was found to be stable between 926.2 and 792.6℃;at low temperatures,however,it decomposed into α-La,α-Fe and LaFe_(4)B_(4),according to the reaction La_(2)Fe_(14)B→α-Fe+α-La+LaFe_(4)B_(4).

Calculation of Cu-rich part of Cu-Ni-Si phase diagram

The thermodynamic calculation of phase equilibria in the Cu-Ni-Si alloy system was carried out using the CALPHAD method. The calculations show that there are three two-phase areas and two three-phase areas in the Cu-rich parts of the isothermal section of the phase diagram at 300-600 ℃,and the three two-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2,FCC-A1(Cu-rich)+δ-Ni2Si and FCC-A1(Cu-rich)+ε-Ni3Si2,two three-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2+δ-Ni2Si and FCC-A1(Cu-rich)+δ-Ni2Si+ε-Ni3Si2. For this reason,an alloy located in the Cu-rich portion may precipitate γ-Ni5Si2,δ-Ni2Si or ε-Ni3Si2;the proportion of each phase depends on the alloy composition and aging temperature. The transmission electron microscope analysis of the Cu-3.2Ni-0.75Si alloy indicates that the precipitates are mainly δ-Ni2Si with only a few γ-Ni5Si2 phase particles,which agrees well with the thermodynamic calculations of phase equilibria.

Phase and CCT Diagram of an N-Containing 8%Cr Roller Steel

The pseudo-equilibrium phase diagram and continuous cooling transformation diagram of an N-containing 8％ Cr roller steel were investigated by using thermodynamic calculation,differential scanning calorimetry,Ⅹ-ray diffraction,expansion method,and so on.Under equilibrium conditions,the main carbonitrides are MX,M7C3,and M23C6 types.The measured Ac1,Ac3,start temperature of martensitic transformation,and M7C3 transformation temperatures are 811,855,324,and 1100 ℃,respectively.Bainite appears at cooling rates ranging from 0.5 to 5 ℃/s and ferrite forms at grain boundaries at a cooling rate lower than 0.5 ℃/s.Finally,the effects of adding N and lowering the C content on workability and mechanical properties of common 8％Cr steel were discussed.

Partial phase diagram of Pd-Ag-Ru-Gd quaternary system

On the basis of the Ag-Pd-Gd, Ag-Ru-Gd and Pd-Ru-Gd ternary systems, the partial phase diagram of Pd-Ag-Ru-Gd（Gd<25% atom fraction） quaternary system has been studied by means of X-ray diffraction analysis, differential thermal analysis, electron probe microanalysis and optical microscopy. The 700℃ isothermal sections of the Ag-Pd-5Ru-Gd, Ag-Pd-20Ru-Gd and Ag-Pd-50Ru-Gd （Gd≤25% atom fraction） phase diagrams were determined respectively. And the 700℃ isothermal section of the Pd-Ag-Ru-Gd （Gd≤25% atom fraction） quaternary system phase diagram was finally inferred. The section consists of four single-phase regions: solid solution Pd（Ag）, （Ru）, Pd3Gd and Ag 51 Gd 14 ; five two-phase regions: Pd（Ag）+（Ru）, Pd（Ag）+ Ag 51 Gd 14 , （Ru）+ Ag 51 Gd 14 , Pd（Ag）+ Pd3Gd and （Ru）+ Pd3Gd; three three-phase regions: Pd（Ag）+ Pd3Gd+（Ru）, Pd（Ag）+ Ag 51 Gd 14 +（Ru） and （Ru）+ Ag 51 Gd 14 + Pd3Gd; one four-phase region Pd（Ag）+ （Ru）+ Ag 51 Gd 14 + Pd3Gd. No new quaternary intermetallic phase is found.

Pt-Pd-Ni体系相图与热力学研究进展

铂基催化剂具有活性高、选择性好、电化学稳定性佳等优点,在工业催化和燃料电池领域具有非常重要的地位。然而,由于成本较高、可用性较低限制了其实际发展。因此,有必要优化铂基催化剂的利用率,设计低成本和高稳定性的铂基催化剂。本研究首先介绍了在燃料电池催化剂领域具有应用前景的Pt-Pd-Ni系合金电催化剂的发展和研究现状,然后详细介绍了Pt-Pd-Ni体系的三个二元系相图与热力学评估数据和研究进展,并对Pt-Pd-Ni三元系的一些实验研究进展和今后的研究工作提出展望,对不同相结构对催化性能的影响进行了分析和讨论。通过Pt-Pd-Ni系相图和相结构等的研究将为燃料电池用新型贵金属合金催化材料的设计及工业应用奠定理论和实验基础。

简析钢铁材料的磁学性质

钢铁制品在日常生活中随处可见;钢铁材料具有磁性也是广为人知的生活常识。实用的钢铁材料种类繁多,磁性的强弱也有显著差别。本文旨在解析这个生活常识背后所涉及的物理知识。总体来看,钢铁材料主要是含有少量碳元素的铁碳合金,此外还可能包含少量其他合金元素。合金元素的含量及种类对钢铁材料磁性的影响很大。本文主要结合铁碳二元合金相图介绍了不同含碳量钢铁材料的组分,并据此对材料磁性的变化进行了定性分析。概括来说,铁磁性主要来自于材料中可能包含的三种组分:铁素体、渗碳体和马氏体,而奥氏体则仅具有顺磁性。其中马氏体是一种处于亚稳状态的非平衡相,无法标记在平衡相图中。本文也可以作为学习和应用相图的一个教学案例。

中子毒物硼和钆在乏燃料后处理中的应用及合金相图研究

随着我国核电站在建及运行的反应堆日渐增多,乏燃料的产生、运输和储存成为核工业面临的严峻难题。对卸载出的巨量核废乏燃料,采用闭环处理循环利用,比传统深埋更加环保和安全。采用添加中子毒物的核结构材料制造相关设备和仪器,可以保障乏燃料后处理过程的运行安全。基于核工业应用要求,针对乏燃料后处理常用的316L不锈钢、Ti35、Zr等材料添加B或者Gd的相图展开调研,结果显示B和Gd可明显提高结构材料的中子吸收效果,但B和Gd的化学性质与过渡族金属Fe,Ti,Zr等相差甚远,除α-Zr最多固溶2.8%Gd(原子数分数)以外,B和Gd均不能大量固溶于常规金属合金体系中,强制添加势必对合金力学性能或耐蚀性能带来巨大危害。可采用团簇模型的合金设计理念,通过含B和Gd化合物相均匀析出或者复合的制造工艺以及Zr-Gd、Ti-Gd体系的多元合金化,引入互溶的中间相,增加难以固溶的元素的固溶度,以此解决中子毒物B和Gd在乏燃料后处理中的应用瓶颈。

Thermodynamic calculation of high zinc-containing Al-Zn-Mg-Cu alloy

Phase fraction and solidification path of high Zn-containing Al-Zn-Mg-Cu series aluminum alloy were calculated by calculation of phase diagram （CALPHAD） method. Microstructure and phases of Al-9.2Zn-1.7Mg-2.3Cu alloy were studied by X-ray diffraction （XRD）, differential scanning calorimetry （DSC） and scanning electron microscopy （SEM）. The calculation results show that η（MgZn2） phase is influenced by Zn and Mg. Mass fractions of η（MgZn2） in Al-xZn-1.7Mg-2.3Cu are 10.0%, 9.8% and 9.2% for x=9.6, 9.4, 8.8 （mass fraction, %）, respectively. The intervals of Mg composition were achieved for θ（Al2Cu）＋η（MgZn2）, S（Al2CuMg）＋η（MgZn2） and θ（Al2Cu）＋S（Al2CuMg）＋η（MgZn2） phase regions. Al3Zr, α（Al）, Al13Fe4, η（MgZn2）, α-AlFeSi, Al7Cu2Fe, θ（Al2Cu）, Al5Cu2MgsSi6 precipitate in sequence by no-equilibrium calculation. The SEM and XRD analyses reveal that α（Al）, η（MgZn2）, Mg（Al,Cu,Zn）2, θ（Al2Cu） and Al7Cu2Fe phases are discovered in Al-9.2Zn-1.7Mg-2.3Cu alloy. The thermodynamic calculation can be used to predict the major phases present in experiment.

低Nb含量的CoCrFeNiNb_x合金退火后的组织演变和性能

在FCC型CoCrFeNi合金中添加少量Nb可起到固溶强化和第二相强化效果,但目前对Nb在FCC相中的溶解度及其对合金组织和性能的影响还不够了解。为此,本文基于热力学计算相图,实验研究了含1%~5%Nb(摩尔分数)的铸态CoCrFeNiNb_x合金在800~1200℃真空退火前后的显微组织和显微硬度。结果表明:即使添加1%Nb,铸态CoCrFeNiNb_x合金中仍存在约3%的FCC+C14共晶组织。后凝固的FCC相中Nb含量可高达2.4%~3.1%,在800℃退火后可析出针状纳米级Mg_(3)Cd型τ相,使合金硬度提高约30HV。经1000℃或1200℃退火后,FCC相的成分均匀,Nb含量分别为1.6%和3.1%,与热力学计算结果一致。退火后,共晶组织中的C14 Laves相球化长大,层片组织消失,合金硬度降低。因此,添加少于3.1%Nb后再进行固溶及时效处理以析出τ相是提高FCC型CoCrFeNi合金强度的有效途径。