550 AND 450°C ISOTHERMAL SECTIONS OF Fe-Ni-C PHASE DIAGRAM

By using WDS method of EPMA and EDS tecbnique of STEM.550 and 450℃ isother- mal sections of Fe-Ni-C phase diagram were determined.

410℃ ISOTHERMAL SECTION OF Al-Cu-Sb PHASE DIAGRAM

The 410℃ isothermal section of the phase diagram of Al-Cu-Sb ternary system has been de- termined by means of X-ray powder diffraction method and electron probe microanalysis. The section determined consists of 12 single-phase regions,21 bi-phase regions and 10 tri-phase regions.

PHASE DIAGRAM OF Nd-Fe-B TERNARY SYSTEM——I.Isothermal Section at Room Temperature

The microstructures of both as-cast and homogenized Nd-Fe-B ternary alloys have been studied. The stable phase regions existing in Nd-Fe-B ternary system at room temperature have been established by the microzone composition analysis and the phase identification. Based on the obtained results, an isothermal section of Nd-Fe-B ternary system at room temperature was drawn.

Isothermal Section of Ag-Cu-Ce(Ce≤34 at%)Phase Diagram at 500℃

The isothermal section of the Ag-Cu-Ce ternary phase diagram at 500℃ containing 0～34 at% Ce have been determined by X-ray diffraction analysis and optical microscopy.It was found that Cu_2Ce-Ag_2Ce pseudo-binary system is characterized by having complete solid solubility at 500℃ and that the solid solubility of silver in Cu_5Ce is up to 41 at% at 500℃.The section consists of eight single phase re- gions,thirteen bi-phase regions and six tri-phase regions.

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).

Primary study of the isothermal phase diagram of the Cu_2O-Al_2O_3-SiO_2 ternary system at 1150℃ in air

The isothermal phase diagram of the Cu2O-Al2O3-SiO2 ternary system at 1150℃ was reported for the samples which were prepared from sol-gel method and quenched by water after being heated at 1150℃ for 12 h. Based on the conventional X-ray powder diffraction （XRD） and in situ high-temperature XRD quantitative analysis,in addition to scanning electron microscopy measurement,the phase identification was achieved. Combining the deduction from the component phase diagrams of the binary systems using the phase equilibrium theorem,the primary isothermal phase diagram was plotted over the composition area Cu2O-mullite-SiO2. In this area,the approximate composition areas of two two-phase regions and one three-phase region,（L2＋Cr）,（L2＋M）,and （L1＋L2＋Tr）,were determined. Moreover,the precise composition areas of both of the three-phase regions （L2＋Cr＋M） and （L2＋M＋A） were determined according to the results of conventional and in situ high-temperature XRD quantitative analysis by Rietveld method.

PHASE DIAGRAM OF Nd-Fe-B TERNARY SYSTEM——Ⅱ.Two Vertical Sections with Constant Nd and B Respectively,Passing Through Nd_2Fe_(14) B Point

According to the experimental data of phase transition taken from DTA, metallography, SEM and microzone composition, two vertical sections of the ternary phase diagram (B=5.88 at.-%, Nd≤45.41 at.-% andNd_2Fe_(14)BNd_(1.1)Fe_4B_4 , B≤44.56 at.-%) have been drawn in detail. It is verified that the crystallization of both Nd_2Fe_(14)B and Nd_(1.1)Fe_4B_4 phase, during cooling from melt, would take peritectic reaction instead of solid-liquid congruent precipita- tion.

The Room Temperature Section of the Phase Diagram of Co-Ge-Sn Ternary System

The room temperature section of the phase diagram of Co-Ge-Sn ternary system has been determined by means of X-ray powder diffraction method.The section determined consists of 12 single-phases,22 two-phase regions,and 11 three-phase re- gions.Two new phases,called δ and η respectively in this paper,have been found.The former is a binary phase with invariable composition(80.46at%Sn)corresponding to formula CoSn_4,and the latter is a ternary phase occuping a homogenous range.The experimental data also show that Co_2Ge phase has a smaller region than that in Ref.1,2,while β-Sn,Ge,CoSn,CoSn_2 and Co_2Ge_3 are phases with invariable compositions.

Isothermal section of Mg-Nd-Gd ternary system at 723 K

An isothermal section of the Mg-Nd-Gd ternary system at 723 K was established by diffusion triple technique and electron probe microanalysis （EPMA）. Mg3Gd and Mg3Nd form a continuous solid solution （Gd,Nd）3Mg, and a continuous solid solution （Gd,Nd）Mg is also formed between MgGd and MgNd. Mg7Gd, Mg5Gd, Mg2Gd, Mg41Nd5, （Gd,Nd）3Mg and （Gd,Nd）Mg are found in the ternary system. In these intermetallic phases, Mg7Gd has been reported to be a metastable phase in previous literatures. The solubilities of Mg, Gd and Nd in all the phases were detected. Furthermore, four three-phase equilibria, α（Mg）＋Mg7Gd＋Mg41Nd5, Mg7Gd＋Mg5Gd＋Mg41Nd5, Mg5Gd＋Mg41Nd5＋（Gd,Nd）3Mg and （Gd,Nd）3Mg＋（Gd,Nd）Mg＋Mg2Gd, were identified in the isothermal section.

Isothermal Section of Er-Mn-Nd Ternary System at 773 K

The isothermal section of the Er-Mn-Nd ternary system at 773 K was investigated mainly by X-ray powder diffraction with the aid of differential thermal analysis. The 773 K isothermal section of the ternary system consists of 9 single-phase regions, 14 two-phase regions, and 6 three-phase regions. At 773 K, the maximum solid solubility of Er in Nd and Nd in Er is about 20%（atom fraction） Er and 26%（atom fraction） Nd, respectively. Er6Mn23 and Nd6Mn23 form a continuous solid solution. The homogeneity range of δ phase extends from about 38% （atom fraction） Er to 43% （atom fraction） Er. No ternary compounds were observed at 773 K in this system.

Isothermal section of Dy-Zr-Si ternary system at 773 K

The isothermal section of the phase diagram of the Dy-Zr-Si ternary system at 773 K was determined by X-ray diffraction (XRD) analysis, metallographic analysis, and scanning electron microscopy (SEM) with energy-dispersive spectrometer (EDS) analysis. The isothermal section consists of 13 single-phase regions, 23 two-phase regions, and 11 three-phase regions. The solubilities of Zr in Dy, Dy5Si4, Dy5Si3, DySi, DySi2, DySi1.67, and Dy in Zr, Zr2Si, Zr3Si2, Zr5Si4, ZrSi, and ZrSi2 were determined at 773 K.

Collins Model and Phase Diagram of 2D Ternary System

The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, someisothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior ofthree-dimensional substances.

DETERMINATION OF ISOTHERMAL SECTION OF Fe-Ni-Zr TERNARY SYSTEM AT 1198K

The isothermal section of Fe-Ni-Zr ternary system at 1198K was experimentally determined using diffusion triple technique together with scanning electron microscopy （SEM） and electron probe microanalysis （EPMA ）. The results indicate that there are seven binary intermetallic phases, Fe2Zr, FeZr2, Nir2, NiZr, Ni10Zr7, Ni7Zr2 and Ni5Nr, found in the temary system, the binary compounds NiZr2 and FeZr2 show a homogeneity range and form a continuous solid solution, namely （Fe, Ni）Zr2 Five three-phase sections, γ（Fe,Ni） ＋ Ni3Zr2 ＋ Ni5Zr,γ（Fe, Ni） ＋ Ni7Zr2 ＋ Ni10Zr7, γ（Fe,Ni） ＋ Fe2Zr ＋ Ni10Zr7, （Fe,Ni）Zr2 ＋ Fe2Zr ＋ Nil0Zr7, and （Fe,Ni）Zr2 ＋ NiZr ＋ Ni10Zr7, exist in the isothermal section. No ternary compound is observed.

PARTIAL PHASE DIAGRAM OF Ag-Cu-Tb SYSTEM

The partial phase diagram of Ag-Cu-Tb system on the Ag-Cu-rich region at room temperature is investigated by X-ray diffraction and optical microscopy analyses. The section consists of six singlephase regions, nine binary phase regions and four ternary phase regions. No ternary intermetallic compound is found.

Determination of isothermal section of Ag-Ti-Zr ternary system at 1 023 K

The isothermal section of Ag-Ti-Zr ternary system at 1023 K was determined by diffusion triple and electron probe microanalysis. The results indicate that four binary intermetallic phases of AgTi, AgTi2, AgZr and AgZr2 are found in Ag-Ti-Zr ternary system at 1 023 K. AgZr2 and AgTi2 form a continuous solid solution, namely Ag(Ti,Zr)2. Four three-phase regions: AgTi +AgZr + Ag, AgTi +AgZr + Ag (Ti, Zr)2, α-Zr +β(Ti, Zr) + Ag (Ti, Zr) 2 and α-Ti +β(Ti, Zr) + Ag (Ti, Zr)2 exist in the isothermal section. No ternary compound is observed.

ISOTHERMAL SECTION OF Mg-Zn-La SYSTEM IN Mg RICH CORNER AT 350℃

Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy （SEM）, electron probe microanalysis with energy dispersive X-ray spectroscopy （EPMA-EDS）, and X-ray diffraction （XRD） have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4 at. pct and the Zn content is 8 at. pct- 48 at. pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm, b=1.121 1.142 nm, c=0.950-0.977 nm.

Determination of isothermal section of Fe-Ti-Zr ternary system at 1173K

Phase relations in the Fe-Ti-Zr ternary system at 1 173 K were investigated by means of diffusion-triple approach together with electron probe microanalysis(EPMA) technique. A series of tie lines and tie-triangles were determined and the isothermal section at 1 173 K was established, which consists of four three-phase fields: β(Ti, Zr)+FeZr2+FeTi, FeZr2+FeTi+Fe2Zr, FeTi +Fe2Zr +Fe2Ti and Fe2Zr +Fe2Ti +Fe. The results show that the largest solubility of Ti in Fe2Zr is about 11.3%(mole fraction) and the solid solubility of Ti in FeZr2 is about 26.9%, the solid solubility of Zr in Fe2Ti is about 8.1% and the solid solubility of Zr in FeTi is 7.2%. The binary compound FeZr2 is nearly a linear compound. No ternary compound is found.

Determination of isothermal section of Ni-Re-Hf ternary system at 1173 K

The phase equilibriua in the Ni Re Hf ternary system at 1173K were investigated by means of diffusion triple technique and electron microprobe analysis(EMPA). The experimental results indicate that two ternary intermetallics (α and β) and five binary intermetallics (Ni 3Hf, Ni 10 Hf 7, Ni 11 Hf 9, NiHf and NiHf 2) exist in the Ni Re Hf system at 1?173 K. A tentative isothermal section of this system at 1?173 K was constructed on the basis of experimental results. The isothermal section consists of nine three phase regions, five of which are supported by the experimental data.

Partial phase diagram of Au-Ag-Dy ternary system

On the basis of Au-Ag, Au-Dy and Ag-Dy binary phase diagrams, the 700℃ isothermal section of Au-Ag-Dy ternary system（Dy≤35%, mole fraction） was established by X-ray diffraction analysis, differential thermal analysis and optical microscopy. It is found that there is a long single-phase region, Au（Ag） or Ag（Au）, along the Au-Ag binary isomorphous system on the gold-silver-rich side of the 700℃ isothermal section and between the binary compound Au2Dy and Ag2Dy there is the all proportional solid solution, （Au2Dy） or （Ag2Dy）. It is confirmed that the partial 700℃ isothermal section consists of six single-phase regions: solid solution Au（Ag） or Ag（Au）, （Au2Dy） or （Ag2Dy）, Au6Dy, Au51Dy14, Au3Dy and Ag51Dy14; nine binary-phase regions: （Au2Dy）+Au（Ag）, Au6Dy+Au（Ag）, Au（Ag）+Ag51Dy14, Ag51Dy14+（Au2Dy）, Au3Dy+（Au2Dy）, Au3Dy+Au51Dy14, Au51Dy14+Au6Dy, Au51Dy14+Au（Ag） and Au（Ag）+Au3Dy;four ternary regions: Ag51Dy14+（Au2Dy）+Au（Ag）, （Au2Dy）+Au（Ag）+Au3Dy, Au（Ag）+Au3Dy+Au51Dy14 and Au51Dy14+Au（Ag）+Au6Dy. No new ternary compound is formed in the gold-silver-rich field（Dy≤35%） of the Au-Ag-Dy ternary system.

773K isothermal section of Gd-Ni-Ti ternary system

The 773?K isothermal section of the Gd Ni Ti system was investigated by X ray diffractometry, optical microanalysis and electron probe microanalysis techniques. The results show that it consists of 13 single phase regions, 23 two phase regions and 11 three phase regions. The maximum solid solubility of Ti in Ni, Gd 2Ni 17 , GdNi 5 and Gd 2Ni 7 are 6.0%, 3.0%, 3.0%, and 2.5%(mole fraction), respectively.