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 Mg-rich corner in Mg-Zn-Al ternary system at 335 °C

The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy dispersive spectroscopy of X-ray (EDS). It is experimentally testified that theα-Mg solid solution is not in equilibrium with the Mg32(Al, Zn)49 (τ) ternary intermetallic compound orq quasicrystalline phase, but only in equilibrium with one ternary intermetallic compound Al5Mg11Zn4 (φ). The whole composition range of theφ phase was also obtained at 335 °C, i.e., 52.5%?56.4% Mg, 13.6%?24.0% Al, 19.6%?33.9% Zn (mole fraction). The solubility of Al in the MgZn phase is remarkably more than that in the Mg7Zn3 phase, and the maximum is about 8.6% Al. Aluminum and zinc are simultaneously soluble in theα-Mg solid solution.

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 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.

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.

Experimental investigation of the isothermal section at 400℃of the Mgsingle bondCesingle bondSr ternary system

The objective of this study is to determine the isothermal section at 400℃ of the Mgsingle bondCesingle bondSr system.In this study,the constitution of the Cesingle bondSr system and the Mgsingle bondCesingle bondSr system have been investigated over the entire composition range using X-ray diffraction(XRD),field emission scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS).No any new binary compound has been found in the Cesingle bondSr system and no ternary compound has been found in the Mgsingle bondCesingle bondSr system also.Nine three-phase regions have been experimentally observed.Six binary phases Mg_(2)Sr,Mg_(23)Sr_(6),Mg_(38)Sr_(9),Mg_(17)Sr_(2),Mg_(12)Ce,Mg_(41)Ce_(5) are detected dissolving about 3-7 at.%the third element.This study first detected the experimental data of the Cesingle bondSr binary system and determined the isothermal section at 400℃ of the Mgsingle bondCesingle bondSr ternary system.

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 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.

Determination of isothermal sections of the Co-Nb-Ni and Ni-Mo-Re ternary systems

The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis（EPMA）.The results indicate that there are three three-phase regions found in the Co-Nb-Ni ternary system at 1373 K：（Ni,Co） ＋ NbCo3 ＋ Ni3Nb,NbCo3 ＋ NbCo2 ＋ Ni3Nb,and NbCo2 ＋ μ ＋ Ni3Nb;and four three-phase regions found in the Ni-Mo-Re ternary system at 1473 K：Re ＋ Ni ＋ χ,Ni ＋ NiMo ＋ σ,σ ＋ χ ＋ Ni,and σ ＋ Mo ＋ NiMo.No ternary compound is observed in the two isothermal sections.The isothermal sections are contrasted with the previous study.

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.

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.

Isothermal Section of Phase Diagram of the Ternary System Co-Dy-Pr at 500℃

The isothermal section of the phase diagram of the ternary system Co Dy Pr at 500℃ was investigated by X ray diffraction analysis, optical microscopy, electron microscopy, electron spectrum and electron probe miscroanalysis techniques. The section consists of seventeen single phase regions, twenty eight two phase regions and twelve three phase regions. Three of single phase regions are the solid continuums and three of single phase regions are the wide limit solid solutions. No ternary compound was observed in this system.

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.

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.

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.

Determination of isothermal sections of Ni-Cr-Nb ternary system

The isothermal sections of Ni-Cr-Nb ternary system at 1 323 K and 1 423 K were determined by means of diffusion triple and energy spectrum analysis （ESA）. By analyzing the diffusion layers in the diffusion couples, the compounds forming in this system were identified. There are three similar compounds found at these two temperatures: Ni3Nb, NiNb and NbCr2-R, and four similar three-phase regions are found: （Ni）+（Cr）+Ni3Nb, Ni3Nb+NbCr2-R+NiNb, NbCr2-R+（Cr）+Ni3Nb, NbCr2-R+NiNb+（Nb）. The results show that no phase transformation happens between these tow temperatures. But the solid solubilities of the binary compounds at 1 423 K become bigger than those at 1 323 K, especially the solid solubility of NbCr2-R. No ternary compound is observed.

1100 ℃ isothermal section of Nb-W-Zr-C quaternary system

An isothermal section of the Nb-W-Zr-C system at 1 100 ℃ was established by means of multiphase diffusion couples along with electron microprobe analysis and X-ray diffraction analysis. The isothermal section consists of two single-phase regions, α（Nb, W, Zr） and （W, Nb）2Zr and one double-phase region, α（Nb, W, Zr）+)（W, Nb）2Zr.) It is concluded that （W, Nb）2Zr is an interstitial intermediate phase with the face-centered cubic （Cu2Mg） lattices. The maximum solid solubility of carbon in （W, Nb）2Zr phase is determined as about 4.18%C（mole fraction）.The composition ranges of tungsten in the （W, Nb）2Zr phase are 55.41% to 65.98% and the maximum solid solubility of niobium in （W, Nb）2Zr is determined as 7.78%.