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Thermodynamic assessment of the ternary system B-Hf-Zr has been conducted by modeling the Gibbs energy of all individual phases using the CALPHAD (CALculation of PHAse Diagrams) approach. There is no ternary compound in this system. The individual solution phases, i.e., liquid, (βHf,βZr), HfB and (Hf,Zr)B2 have been modeled. The modeling covers the whole composition and temperature ranges. The Gibbs energies of HfB2 and HfB in the B-Hf system were reassessed using the two-sublattice models (B,Hf)1(B,Hf)2 and (Hf)1(B,Hf)1, respectively. A set of self-consistent thermodynamic parameters for the B-Hf-Zr system was obtained by considering the phase diagram data in the ternary system. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information was satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme of the B-Hf-Zr system are also presented.

Phase equilibria during solidification in the Al-Cr-Co system in the range of compositions 0-70 at.% Al were studied using optical microscopy, scanning electron microscopy, electron probe microanalysis, differential thermal analysis and x-ray diffraction. Solidus and liquidus surfaces, a melting diagram as their superposition, a Scheil diagram for solidification, as well as series of isopleths were constructed for the first time. Solid solutions based on Cr, αCo, Cr5Al8 (γ3 and γ1 phases), CoAl, Co2Al5 binary compounds and the ternary compound τ5 take part in phase equilibria. The monoclinic ternary compound τ5 forms by peritectic reaction L + γ1 + Co2Al5 ↔ τ5 at 1065 °C. Four invariant four–phase reactions and one invariant three–phase reaction involving liquid take place at 1280, 1175, 1110, 1065 and about 1480 °C, respectively. Isopleths 10, 20, 30 and 40 at.% Al as well as 40 at.% Cr demonstrate peculiarities of the phase diagram.

The isothermal sections of the Al–Cr–Ta ternary system at 1000 and 1200 °C have been determined by means of electron probe microanalysis and x-ray diffraction. The results show that eleven and nine three-phase regions are determined in the isothermal sections at 1000 °C and 1200 °C, respectively. No ternary compound exists at both two isothermal sections. The addition of Cr makes the Al69Ta39 phase be stable at 1000 °C. The Cr2Ta(HT) phase has a large composition range at both two isothermal sections. The experimental information obtained in the present work could be significant for alloy design and the complement of the thermodynamic database.

The 450 and 600 °C isothermal sections of the Ni-V-Zn ternary system have been investigated through Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and x-ray Diffraction (XRD) technique. Eight three-phase regions have been confirmed at the 450 °C section and nine three-phase regions exist at the 600 °C one. Experimental results indicate that it is difficult for Ni to dissolve in VZn3 and V4Zn5. The solid solubilities of V in γ(Ni2Zn11) and β1(NiZn) are 1.4 and 3.7 at.% at 450 °C, respectively, while V in γ and β1 are 2.5 and 4.0 at.% at 600 °C, respectively. The solid solubilities of Zn in Ni2V7, σ(Ni2V3), Ni2V and Ni3V are 0.5, 4.7, 2.3 and 2.6 at.% at 450 °C as well as 0.5, 9.5, 2.2 and 2.8 at.% at 600 °C, respectively. No ternary compound has been found in this work.

The thermodynamic modeling of the ternary system C-Cr-Zr has been obtained by modeling the Gibbs energy of all individual phases using the CALPHAD (CALculation of PHAse Diagrams) approach. There is no ternary compound in this system. The liquid is modeled as a substitutional solution phase, while the solid solution phases including ZrC, (αZr), (βCr), (βZr), Cr3C2, Cr7C3, Cr23C6, C14, C15 and C36 are described by sublattice models. The modeling covers the whole composition and temperature ranges. A set of self-consistent thermodynamic parameters for the C-Cr-Zr system is obtained by considering the phase diagram data in the ternary system. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme of the C-Cr-Zr system are also presented.

Using CALPHAD method, the Al-Zr, Al-Li and Al-Li-Zr systems have been reassessed based on the latest experimental phase relations from literatures and the first-principle calculation of the formation enthalpy for ternary compound T1(AlLi2Zr) in this work. The excess Gibbs energies of solution phases, including liquid, bcc, fcc and hcp, were expressed by the Redlich–Kister polynomial. The stoichiometric compounds, i.e. Al4Zr5, Al3Zr5, AlZr2, AlZr3, Al2Li3, Al4Li9 and T1(AlLi2Zr), were modeled as stoichiometric model and the non-stoichiometric compounds, i.e. Al3Zr, Al2Zr, Al3Zr2, AlZr, Al3Zr4, Al2Zr3, AlLi2 and T2(AlLix+yZr5−x), were described with different sublattice models. Finally, a set of reasonable thermodynamic parameters for Al-Li-Zr ternary system have been obtained, which notes a clear improvement on the self-consistency. The calculated isothermal section at 470 K of Al-Li-Zr system was in reasonable agreement with the experimental one.

Phase equilibria in the Co–Fe–La system were studied using differential thermal analysis (DTA), X-ray diffraction analysis, scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Liquidus and solidus projections and a melting diagram for this system over the whole concentration range and a Scheil diagram for solidification were constructed. The ternary compound (Co,Fe)17La2 (τ) (Th2Zn17-type structure) forms by peritectic reaction L + (γCo,Fe) + Co13La ⇄ τ at 978 °C. This ternary compound is located along the isoconcentrate of 11 at.% La and extends from 45.8 to 79.3 at.% Co. The Co13La phase has the widest homogeneity region and dissolves up to 43.3 at.% Fe. The solubilities of Fe in Co5La, Co7La2, Co19La5, and Co3La2 were established to be 10.3, 9.2, 4.7, and 3.2 at.%, respectively. The solubility of Fe in Co1.7La2 and CoLa3 according to EPMA does not exceed 1 at.%. The maximum solubility of La in (γCo,Fe) and (αCo,Fe) is determined to be less than 1 at.%.

The phase relationships of the Ce-Pr-Fe ternary system at 600 °C were experimentally investigated using equilibrated alloys and diffusion junction samples with the use of electron probe microanalysis, x-ray diffraction, and scanning electron microscopy. The isothermal section of the Ce-Pr-Fe system at 600 °C consists of 7 single-phase, 11 two-phase, and 5 three-phase regions. No ternary compound was found. The PrFe2 phase was observed in both ternary alloys and diffusion samples at normal pressure. The solid solubility of Ce in PrFe2 and Pr2Fe17 is 1.76 and 3.75 at.%, respectively. The solid solubility of Pr in CeFe2 and Ce2Fe17 is 13.21 and 0.77 at.%, respectively.

Phase transformations in the Zr-Co-Sn ternary system have been studied at crystallization using differential thermal analysis (DTA), x-ray diffraction analysis, scanning electron microscopy, and electron probe microanalysis. The solidus surface of this system over the whole concentration range is constructed for the first time, involving 20 three-phase regions. Four ternary compounds, viz. ZrCo2Sn (τ1), ZrCoSn (τ2), Zr6Co1.65Sn1.35 (τ3), and Zr5Co6Sn18 (τ4), are confirmed. It is shown that they exist at the solidus temperatures. The crystal structure of the compound τ4 is first established as Tb5Rh6Sn17-type (cF116-Fm-3m) with lattice parameter a =13.376(6) A. Only one ternary compound (ZrCo2Sn, τ1, Heusler phase) has a rather wide homogeneity range at solidus temperature (43.5–50 at.% Co along the 50Zr50Sn-Co ray). Binary compounds Zr5Sn3+x and ZrCo2 dissolve up to 9 at.% Co and 14.5 at.% Sn, respectively. All other compounds are practically linear phases. The above six phases define the character of the solidus projection, taking part in all three-phase equilibria, except for those with participation of Sn.

Phase relationships in the Nd-Ce-Fe ternary system at 773 K have been investigated mainly by x-ray diffraction and scanning electron microscopy with energy disperse spectroscopy techniques. The isothermal section consists of 6 single-phase regions, 7 two-phase regions and 3 three-phase regions. No ternary compound is observed in this system. Nd2Fe17 and Ce2Fe17 are found to form a continuous solid solution (Nd,Ce)2Fe17, and the solubilities of Ce in Nd5Fe17 and Nd in CeFe2 are determined.

In this study, the phase equilibria of the Cr-Mo-Hf ternary system at 1100 and 1300 °C were experimentally investigated by means of back-scattered electron, electron probe microanalysis and x-ray diffraction. The two C15 phases (α(HfMo2) and α(HfCr2)) link up with each other from Mo-Hf side to Cr-Hf side across the isothermal sections both at 1100 and 1300 °C. The isothermal section at 1300 °C consists of one three-phase region and three two-phase regions, while no ternary compound is found. One single-phase region of bcc(βHf) not connected with Mo-Hf binary boundary is found unexpectedly at 1100 °C, which results in the appearance of two extra three-phase regions.

The 600 and 800 °C isothermal sections of the Al-Ni-Sn ternary system were determined based on examination of equilibrated alloys by SEM spectroscopy and x-ray powder diffraction. Nine and Six three-phase regions exist in the Al-Ni-Sn system at 600 and 800 °C respectively. All the Al-Ni and Sn-Ni binary compounds except Al3Ni4 were confirmed at 600 °C, no ternary compound exists in Al-Ni-Sn system. The Ni3Sn2, Ni3Sn and AlNi3 phases show a large solubility of the third element. No ternary compound exists in Al-Ni-Sn system.

The isothermal section of the Al-Si-Ti ternary system at 550 °C has been determined using scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. Results show that there are 12 three-phase equilibrium regions in the isothermal section of the system. The maximum solubility of Si in Al3Ti is 16.4%, and the solubility of Al and Ti in Si is small. There exists only one ternary compound in the isothermal section with a composition of Al7.1-13.9Ti33.5-34.2Si51.9-59.1.

The 600 and 800 °C isothermal sections of the Al-Sb-Cr ternary system were studied by scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction. No ternary compound was found in this system at either 600 or 800 °C. AlSb can equilibrate with all phases in both the 600 and 800 °C isothermal sections except Cr. Ten three-phase regions were clearly identified in the Al-Sb-Cr ternary system at 600 °C and seven three-phase regions were confirmed in the 800 °C isothermal section.

The phase equilibria of the Co-Ti-Ru ternary system at 1000, 1100, and 1200 °C were studied using the electron probe microanalyzer and x-ray diffraction. The results show that: (1) no ternary compound exists in the isothermal sections from 1000 to 1200 °C; (2) the phases of CoTi and TiRu form the continuous solid solution phase (Co,Ru)Ti; (3) the solubility of Ru in the Co3Ti phase is less than 5 at.% at isothermal sections 1000-1100 °C. These experimental results will provide useful information for the foundation for alloy design and the supplement for thermodynamic databases.

The thermodynamic description of the ternary system B-Ti-Zr has been obtained by modelling the Gibbs energy of all individual phases using the CALPHAD (CALculation of PHAse Diagrams) approach. There is no ternary compound in this system. The individual solution phases, i.e. Liquid, (βTi, βZr), TiB, (Ti, Zr)B2 and ZrB12 have been modeled. The modeling covers the whole composition and temperature ranges. The Gibbs energy of ZrB2 in the B-Zr system was reassessed using the two-sublattice model (B, Zr)1(B, Zr)2. A set of self-consistent thermodynamic parameters for the B-Ti-Zr system was obtained by considering the phase diagram data in the ternary system. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data showed that the experimental information was satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme of the B-Ti-Zr system have also been presented.

Phase equilibria of the Al-Mn-Sn system were investigated by means of x-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopy. Two isothermal sections of the Al-Mn-Sn system at 450 and 800 °C were experimentally established. No ternary compound was found at those two temperatures. The low-temperature phase Mn3Sn2 was observed at 450 °C. The solubility of Al in Mn3Sn, Mn3Sn2, MnSn2 and that of Sn in Al8Mn5 at 450 °C is about 3.1, 2.9, 0.6, and 1.7 at.%, respectively. The high-temperature phase Mn2-xSn was observed at 800 °C. The solubility of Al in Mn3Sn, Mn2−xSn and that of Sn in Al8Mn5 at 800 °C was measured to be 2.8, 3.6 and 1.0 at.%, respectively. Al12Mn, also named G phase, was proved to be stable at 450 °C.

In this work, the phase relationship of V-Si-Y ternary system at 1073 K has been experimentally investigated using the combination of x-ray powder diffraction and scanning electron microscopy with energy-dispersive x-ray analyses using equilibrated alloy method. The existence of eight binary compounds, namely, VSi2, V6Si5, V5Si3, V3Si, Y3Si5, YSi, Y5Si4, and Y5Si3 has been confirmed. Y2Si3 and YSi2 were not found at 1073 K. No ternary compound was found at 1073 K in this system. The maximum solid solubility of Si in the (V) phase is about 4.0 at.%. The range of homogeneity of V3Si was from 20.4 to 25.4 at.% Si. No remarkable solid solubility of the elements in any other phase was observed. This isothermal section consists of nine three-phase regions, 19 two-phase regions and 11 single-phase regions.

The phase equilibria of the Co-Cu-Mo ternary system at 900 and 1100 °C have been studied by using x-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS). Three and five three-phase regions have been confirmed in the system at 900 and 1100 °C, respectively. No ternary compound has been found in these two isothermal sections. At 900 °C, the maximum solubilities of Co and Cu in the μ phase are 56.5 and 4.4 at.%, respectively. As the temperature rises to 1100 °C, their solubilities decrease slightly. Moreover, with the temperature increases from 900 to 1100° C, in the αCo phase, the solubility of Mo increases from 6.5 to 11.9 at.% and the solubility of Cu increases from 8.3 to 12.1 at.%.

The isothermal section of the Zr-Si-Y ternary system at 900 °C has been investigated using x-ray power diffraction, Scanning electron microscopy coupled with energy-/wave-dispersive x-ray spectroscopy. Nine three-phase equilibrium regions were determined experimentally. No ternary compound was observed in the present work. The 9 binary compounds Zr2Si, Zr3Si2, Zr5Si4, ZrSi, ZrSi2, Y5Si3, Y5Si4, YSi and Y3Si5 were confirmed to exist in the Zr-Si-Y ternary system at 900 °C. The solubility of the third component in the binary compound was determined experimentally.

The interaction of components in the Dy-Sm-Ge system at 873 K was investigated by means of x-ray phase and structural analyses, microstructural analysis and energy dispersive x-ray spectroscopy. The existence of the continuous solid solutions between the isostructural binary germanides of the Dy1−xSmxGe (CrB-type), Dy5-xSmxGe4 (Sm5Ge4-type) and Dy5-xSmxGe3 (Mn5Si3-type) were established. The limited solid solutions based on the binary germanides of the SmGe2 (α-ThSi2-type), DyGe2 (TbGe2-type) and Dy11Ge10 (Ho11Ge10-type) are formed. The solubility of Dy in SmGe2 is 15 at.%, Sm in DyGe2 and Dy11Ge10 − 10 at.%, Sm. Two ternary SmxDy1−xGe1.5 (x = 0.15-0.50) and Sm2Dy2Ge7 compounds were found. SmxDy1−xGe1.5 crystallizes in AlB2 structure type. The crystal structure of the new ternary compound of the Sm2Dy2Ge7 (ordered superstructure to Nd4Ge7-type, Pearson symbol oS44, space group C2221, a = 0.5942(1), b = 1.3823(4), c = 1.1801(3) nm, V = 0.9694 nm3) was investigated by means of x-ray single crystal diffraction. The germanium atoms form 3D anionic network the existence of which was confirmed by electronic structure calculations.

The 650 and 750 °C isothermal sections of the Cr-Sb-Fe ternary system were determined by means of scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction. More than 40 alloys were prepared by a powder metallurgy method. Two continuous solid solution phases (Fe, Cr)Sb and (Fe, Cr)Sb2 were clearly identified. Two three-phase regions have been confirmed in the Cr-Sb-Fe ternary system at 650 and 750 °C isothermal sections. No ternary compound was found in this system.

Insight into the phase equilibria, intermetallic compounds, solid solution and thermodynamic properties of the system of Zr, Si and rare earth elements is of academic interest for development of key structural materials in many fields. In this work, the solid state phase equilibria of the Si-Y-Zr ternary system at 1173 K were experimentally investigated by using x-ray powder diffraction and backscattered electron with energy dispersive x-ray analysis. The existence of 10 binary compounds namely, SiZr2, α-Si4Zr5, Si2Zr3, Si2Zr, α-SiZr, α-Si2Y, β-Si5Y3, SiY, Si4Y5 and Si3Y5, have been confirmed in this system at 1173 K, respectively. No binary compound was found in the Y-Zr binary system, and no ternary compound was found in current ternary system. The solid solubility of Y in the phases SiZr2, α-Si4Zr5, Si2Zr3, Si2Zr, α-SiZr, and Zr in α-Si2Y, β-Si5Y3, SiY, Si4Y5 and Si3Y5 was determined at 1173 K.

The 600 °C isothermal section of the Zn-Al-La ternary system was experimentally determined using scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction and equilibrated alloy method. The results indicate that nine three-phase regions have been identified in the Zn-Al-La ternary system at 600 °C. No new ternary compound was found in the system. La-Zn and La-Al compounds can dissolve a certain amount of Al and Zn, respectively. The solubility of Al in LaZn, LaZn5 and La3Zn22 phases is 18.6, 2.6 and 9.0 at.%, respectively, and the solubility of Al in La2Zn17 and LaZn11 phases is 17.1 and 6.3 at.%, respectively. The solubility of Zn in Al4La5, AlLa, Al2La and Al3La phases is 7.8, 7.8, 25.3 and 15.2 at.%, respectively. The ternary compound Zn2Al2La has a larger composition range, and its chemical composition can be roughly expressed as La (ZnxAl1−x)4 (0.2875 ≤ x ≤ 0.6875).

Phase relationships in the Fe-Mn-Sn ternary system at 723 K were investigated using equilibrated approach. More than 40 alloys were prepared by arc-melting method and examined by x-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopic. The existence of five binary compounds FeSn, FeSn2, MnSn2, Mn3Sn2, Mn3Sn and one intermediate solid solution γ(Fe, Mn) have been confirmed in this system. FeSn2 and MnSn2 form continuous solid solution (Fe1−x, Mn x )Sn2 (0 ≤ X ≤ 1) and the lattice parameters of (Fe, Mn)Sn2 reduced linearly with increasing of Fe content. At 723 K, the maximum solid solubilities of Fe in αMn, βMn, Mn3Sn, Mn3Sn2 phases and Mn in FeSn, αFe are about 25, 34.8, 37.3, 46.2 at.% Fe and 26.8, 5.5 at.% Mn respectively. The solid solubilities of γ(Fe, Mn) ranged from 42.1 to 78.1 at.% Fe and the limited solubility of Sn is around 3 at.%. The isothermal section consists of 6 three-phase regions, 13 two-phase regions and 9 single-phase regions. No ternary compound was found at 723 K in this system.

The isothermal section of the Zr-Sn-Cu ternary system at 700 °C was investigated by using x-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. A new ternary compound τ (Zr25.3Cu66.1Sn8.6) was observed in the Cu-rich corner of this system. The previous known ZrCuSn and ZrCuSn2 ternary compound were confirmed.

The 450 and 600 °C isothermal sections of the Zn-Cr-Si system were experimentally constructed using scanning electron microscopy equipped with energy dispersive x-ray spectrometry, and x-ray diffraction. Six three-phase regions in the 450 °C section and five three-phase regions in the 600 °C section were identified experimentally. No ternary compound was found. Si has low solubility in CrZn17. The Zn solubility in CrSi2, Cr5Si3, and Cr3Si are all less than 2.2 at.%. The CrSi phase cannot be in equilibrium with the η-Zn phase. Thermodynamic extrapolation of the Zn-Cr-Si system was carried out and showed good agreement with experimentally determined phase relationships.

The Zn-rich corner of the Zn-Cu-Ti-RE(Ce, La) quaternary systems at 450 °C have been experimentally investigated by scanning electron microscopy coupled with energy dispersive x-ray spectrometer and x-ray diffraction. The liquid containing phase regions have been well identified in these two systems. The ternary compound τ (Cu2TiZn20) can equilibrate with all phases in the Zn-rich corner of these two systems. Neither Ce nor La can dissolve into TiZn16, e(CuZn4) and τ(Cu2TiZn20). While the solubility of Cu in CeZn11 and LaZn13 can reach 2.9 at.% and 5.0 at.%, respectively. The results can help to design and analyze the Zn-Cu-Ti-RE alloys.

Isothermal section of Fe-Gd-Pd ternary system at 873 K has been established by means of x-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscope (SEM) with energy disperse x-ray spectroscopy (EDS) in backscattered electron imaging modes. The isothermal section consists of 14 single-phase regions, 25 two-phase regions, and 12 three-phase regions. At 873 K, no ternary compound was found and the binary inermetallic compounds Gd3Pd and Fe23Gd6 are not stable, whereas the compound Fe23Gd6 decomposes into compounds Fe17Gd2 and Fe3Gd. The XRD and the SEM/EDS analysis show that there is almost no solubility of Gd in the FePd and FePd3 phases, and the solubilities of Pd in Fe17Gd2, Fe3Gd and Fe2Gd and Fe in GdPd2, α-Gd3Pd4 and Gd3Pd2 are all less than 1 at.%. Meanwhile, the solubilities of Fe in GdPd3, α-GdPd and Gd7Pd3 are determined to be as high as 1.37, 5.31, and 4.18 at.% Fe, respectively.

Through alloy sampling approach, phase equilibria in the Cu-Co-Zr ternary system have been determined. Based on the phases identified with electron probe microanalysis and x-ray diffraction, isothermal sections at both 873 and 1200 K were constructed. No ternary compound was detected. It is evident that remarkable ternary solubility occurs in almost all binary intermetallic phases at both temperatures. For instance, solubility of Co in Cu51Zr14 can be up to 17.6 and 27.5 at.% at 873 and 1200 K, respectively. Besides, continuous dissolution between CuZr and CoZr at 1200 K was observed, and the maximum content of Cu in CoZr at 873 K reaches to 42.5 at.%.

The phase equilibria of the Co–V–Sn ternary system at the 900 and 1000 °C sections were investigated experimentally by means of electron probe microanalysis and x-ray diffraction analysis. Seven three-phase regions were found in the isothermal section at 900 °C and six triphase regions at 1000 °C. The Heusler-type ternary compound Co2VSn was confirmed at 900 °C in the composition ranges of 36.7–57.6 at.% Co and 11.8–20.9 at.% Sn, becoming slightly wider at the higher temperature of 1000 °C. Sn dissolves in α(Co), Co3V, and σ-Co2V3 phases with low solubility. V is almost insoluble in liquid, with solubility of less than 0.5 at.%. The solubility of Co in V3Sn phase increased with temperature, from 4.4 at.% at 900 °C to 11.6 at.% at 1000 °C.

The isothermal section at 600 °C of the La-Zn-Si system was established by using equilibrated alloys and the diffusion couple technique. Microstructural observation and phase identification were performed using optical microscopy, scanning electron microscopy with energy dispersive x-ray spectroscopy and a wave dispersive x-ray spectrometer, and x-ray powder diffraction. Seven ternary compounds were identified in this ternary system, and temporally designated as τ 1, τ 2, τ 3, τ 4, τ 5, τ 6 and τ 7. Two previously reported ternary compounds, viz. τ 1 and τ 2, were found to exist at 600 °C. EDS analysis revealed that the τ 1 phase contained Si from 2.4 to 6.1 at.% and La from 22.3 to 23.3 at.%. The compositional region of the τ 2 single-phase ranged from 28.3 to 40.7 at.% for Si and from 31.5 to 33.1 at.% for La. Two new ternary phases, τ 5 and τ 6, were identified. The τ 5 phase with the CeNiSi2-type was determined to have a composition range of 36.9-39.2 at.% Si for about 24 at.% La. The τ 6 phase with the ThCr2Si2-type was found to have a composition range of 18.9-19.7 at.% La and 27.4-30.6 at.% Si. The crystal structures of τ 3, τ 4, and τ 7 were not determined. The solubility of Si in LaZn13, LaZn11, La2Zn17, La3Zn22, and LaZn5 was negligible, and that of Si in LaZn4, LaZn2 and Zn in LaSi2, La3Si2 was determined as 5.1, 2.3, 16.2 and 3.8 at.%, respectively.

The 600 °C isothermal section of the Al-Ni-Zn ternary system was constructed based on wave dispersive x-ray spectrometry and x-ray power diffraction analysis. Eight three-phase regions have been identified in the Al-Ni-Zn ternary system at 600 °C. No new ternary compound was found in the system. The Liq. phase (η-Zn) can be in state of equilibrium with the Al3Ni, Al3Ni2 and AlNi phases. The solubility of Ni in the Liq. phase is low, no more than 0.8 at.%. Binary phases AlNi and NiZn extend into the ternary system, and they co-exist in the Al-Ni-Zn ternary system at 600 °C. The three-phase triangles of (NiZn + AlNi + Ni3Zn14) and (AlNi3 + AlNi + NiZn) are constructed in this ternary system. As shown in this research result, the three-phase equilibrium relationship of the phases AlNi, Al3Ni5 and AlNi3 has been confirmed in the present study.

The isothermal section of the Cu-Fe-Si ternary system at 650 °C was investigated by scanning electron microcopy, coupled with energy dispersive x-ray spectroscopy and x-ray diffraction. Seven three-phase regions exist in the isothermal section of the Cu-Fe-Si ternary system. No new ternary compound was found in this section. The solubility of Fe in η(Cu3Si), e(Cu15Si4), γ(Cu5Si) and κ(Cu6.69Si) phases was low. The solubility of Fe in (Cu) was found to decrease when Si content was increased in the range from 5.3 at.% to 11.9 at.%. The maximum solubilities of Cu in FeSi, FeSi2 and (αFe) were 1.7 at.%, 3.3 at.% and 1.6 at.%, respectively, and the maximum solubilities of Si in (Cu) and (αFe) were 11.9 at.% and 27.1 at.%, respectively.

Phase equilibria of the Cu-Sn-Bi ternary system have been investigated by means of x-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry analysis. Cu-Sn-Bi alloys were prepared and equilibrated at 250, 450 and 700 °C, and the equilibrium phases were experimentally identified. Isothermal sections at these three temperatures were proposed based on the experimental results and the information on the three constituent binary systems. Moreover, the solubility of the Bi in the Cu-Sn compounds is less than 0.8 at%. No ternary compound was found. The phase equilibria between the liquid and the solid phases appears to be inclined towards the Bi-corner at all temperatures.

B-Mo-Nb alloys, as-cast and annealed at subsolidus temperatures, were experimentally studied by x-ray diffraction technique and scanning electron microscopy with electron probe microanalyses. Temperatures of incipient melting were measured by pyrometry after Pirani and Alterthum. No ternary compound was found in the examined alloys. Based on the experimental data, the B-Mo-Nb phase diagram was constructed for the first time, including liquidus and solidus surface projections and Scheil’s reaction scheme.

The 450 °C isothermal section of the Si-V-Zn ternary phase diagram was experimentally determined using x-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy. All the six three-phase regions were well determined. No ternary compound was found. Si5V6 was not detected at 450 °C. All the Si-V compounds can equilibrate with the liquid-Zn phase. And the V-Zn compounds, VZn3 and V4Zn5, can equilibrate with SiV3. In addition, the maximum solubilities of Zn in Si2V, Si3V5 and SiV3 were 1.0, 1.7 and 4.8 at.%, respectively, while Si had no detectable solubility in Zn-V compounds. Furthermore, thermodynamic extrapolation of the Si-V-Zn system was carried out using only the binary interaction parameters. This showed good agreement with the experimentally determined three-phase fields.

Phase equilibria of the Ag-Cu-Sb system were experimentally determined by electron probe microanalyzer and x-ray diffraction. Three isothermal sections of the Ag-Cu-Sb ternary system at 300, 500 and 600 °C were experimentally established, and no ternary compound was found in this system. Experimental results show that the liquid phase region increases with the temperature increase in region from 500 to 600 °C. The newly determined phase equilibria in this system will provide important information for the development of lead-free solders.

The phase equilibria at 500 °C of the Mg-Gd-La system were investigated via a combination of a diffusion couple technique and an equilibrated alloys method, by means of the electron probe microanalyses and x-ray diffraction technique. The LaMg2 and La5Mg41 phases in the Mg-La system were found to exist stably at 500 °C. Continuous solid solutions of (Gd,La)Mg and (Gd,La)Mg3 form between GdMg and LaMg and between GdMg3 and LaMg3, respectively. No ternary compound was found. Five three-phase equilibria, i.e. (Mg) + LaMg12 + GdMg5, LaMg12 + La2Mg17 + GdMg5, GdMg5 + La5Mg41 + (Gd,La)Mg3, GdMg2 + (Gd,La)Mg3 + (Gd,La)Mg and LaMg2 + (Gd,La)Mg3 + (Gd,La)Mg, were accurately determined. The isothermal section at 500 °C was constructed in the present work.

The phase equilibria of the Sn-Zn-Sb ternary system at 400 and 500 °C were experimentally determined by electron probe microanalyzer, x-ray diffraction and differential scanning calorimetry. In this study, the ternary compound of (Zn,Sn)Sb is confirmed at 400 and 500 °C. Additionally, a liquid phase region is found at 400 °C with composition ranges of 9.09-12.86 at.% Zn and 31.47-34.22 at.% Sn, which becomes a prolongation of the main liquid as the temperature is raised to 500 °C.

The 600 °C isothermal section of the Zn-Co-Sb ternary system has been determined experimentally by means of scanning electron microscopy coupled with energy-dispersive spectrometry and x-ray diffraction. Nine three-phase regions could be confirmed in the isothermal section at 600 °C. Moreover, a new ternary compound named CoSbZn was positively identified for the first time in this study, containing 25.8 to 39.0 at.% Co, 28.9 to 36.4 at.% Zn and 31.4 to 38.0 at.% Sb. The experimental results indicated that the maximum solubility of Co in the L phase was less than 2.4 at.%.

The isothermal section of the Dy-Mn-As ternary system at 773 K has been investigated by using x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. This isothermal section consists of 12 single-phase regions, 21 two-phase regions and 10 three-phase regions. The highest solid solubility of Dy in MnAs is about 0.65 at.%Dy, and that of Mn in DyAs is less than 0.79 at.%Mn. The maximum solubility of As in DyMn2 is less than 0.33 at.%As. No ternary compound was found to exist in this section at 773 K.

Phase relations of Ti-Mn-Zr ternary system at 1020 and 800 °C have been investigated mainly by metallographic observations, x-ray diffraction and electron microprobe analysis.A new ternary compound named K was detected, which shows a remarkable homogeneity range both at 1020 and 800 °C. The isothermal section at 1020 °C contains 8 single-phase regions, 13 two-phase regions and 6 three-phase regions, while the isothermal section at 800 °C consists of 9 single-phase regions, 15 two-phase regions and 7 three-phase regions. The continuous solid solution (Ti,Zr)Mn2 shows a wide homogeneous range both at 1020 and 800 °C, and the phase TiMn4 exists at 1020 °C and disappears at 800 °C.

Isothermal sections of the Al-Ce-Zn ternary system in the Ce-poor regions (≤33.3 at.%Ce) at 450 and 600 °C were determined experimentally using the equilibrated alloy approach. Twelve three-phase regions were identified at both 600 and 450 °C. The ternary compound τ (Al2CeZn2) was well confirmed. Its Ce content is around 20 at.% and at 600 °C the Zn content spans 27.5-71.6 at.%, while correspondingly, the Al content spans 53.3-8.1 at.%. At 450 °C the span is similar, but somewhat less. The a lattice parameter for τ increases with Al concentration at lower Al contents in the span, whereas the c lattice parameter increases with Al concentration at higher Al contents in the span. The maximum solubility of Zn in Al11Ce3 and Al2Ce at 600 °C is 17.9 and 20.7 at.%, respectively. And that of Al in CeZn11, Ce2Zn17, Ce3Zn22, CeZn5, Ce13Zn58, Ce3Zn11, CeZn3, and CeZn2 at 600 °C is 12.5, 17.6, 4.9, 2.5, 0.6, 2.2, 6.3, and 32.4 at.%, respectively. All these solubilities decrease a little when the temperature turns to 450 °C.

The phase equilibria at 500 °C of the Mg-Gd-Nd system were investigated via a combination of a diffusion couple technique and the equilibrated alloys method, by means of the electron probe microanalyses and x-ray diffraction technique. It was revealed that continuous solid solutions of (Gd,Nd)Mg and (Gd,Nd)Mg3 form between GdMg and NdMg and between GdMg3 and NdMg3, respectively. No ternary compound was found. 3 three-phase equilibria, i.e. (Mg)+Nd5Mg41+GdMg5, Nd5Mg41+GdMg5+(Gd,Nd)Mg3 and (Gd,Nd)Mg3+GdMg2+(Gd,Nd)Mg, were well determined. In addition, the homogeneity ranges of the binary phases in the Mg-Gd and Mg-Nd systems were also well measured. The metastability of the NdMgl2 and GdMg7 phases were confirmed and the isothermal section at 500 °C was constructed in the present work.

Phase diagram of the Zn-V-Sb ternary system has been studied experimentally by means of scanning electron microscopy coupled with energy-dispersive spectrometric and x-ray diffraction. Twelve different tri-phase regions could be confirmed in this system at 450 °C. Moreover, a new ternary compound named VZnSb, whose composition range spanned from 30.4-32.4 at.% V, 30.5-34.0 at.% Zn and 34.7-37.1 at.% Sb, is positively identified for the first time, and the crystal structure of VZnSb is not resolved. The VZnSb phase could be equilibrated with V3Sb, SbZn, Sb2Zn3, Sb3Zn4 and η-Zn. Experimental results indicated that the solubility of V in SbZn, Sb3Zn4, Sb2Zn3 and α-Sb is very limited. On the other hand, the maximum solubility of Zn in VSb2, VSb and V3Sb is up to 1.8, 9.1 and 3.7 at.%, respectively. The solubility of Sb in VZn3 is up to 0.4 at.%, and η-Zn dissolves up to 1.3 at.% V and 2.0 at.% Sb.

The phase equilibrium of the Ti-Ta-Sn ternary system at 1173 K was investigated experimentally using x-ray diffraction, scanning electron microscopy, and electron probe microanalysis. The isothermal section on the whole composition range was constructed, where eight single-phase regions and seven three-phase regions coexisted. The ternary compound Ti36Ta28Sn36 was found in the experiment, and two three-phase regions β-Ti6Sn5 + Ti36Ta28Sn36 + Ta3Sn and Ti2Sn + Ti3Sn + β(Ti, Ta) were experimentally detected. Experimental analysis shows that the solid solution β(Ti, Ta) dissolves up to approximately 21.2 at.% Sn, and that the maximum solubility of Ta in Ti3Sn and Ti5Sn3 can reach up to 9.3 and 5.9 at.%, respectively. The solubility values of Ta in Ti2Sn and β-Ti6Sn5 are no less than 7.3 and 15.5 at.%, respectively, whereas that of Ti in Ta3Sn is no less than 8.8 at.%. The liquid phase mainly exists in the Sn-rich corner.

The crystal structure of W1−x B3 has been reinvestigated by x-ray single crystal diffraction and revealed isotypism with the Mo1−x B3 structure type (space group P63/mmc; a = 0.52012(1), c = 0.63315(3) nm; R F = 0.040). As a characteristic feature of the structure, planar hexagonal metal layers (1/3 of atoms removed from ordered positions) sandwich planar boron honeycomb layers. One of the two W-sites shows a random defect of about 73%. Strong metal boron and boron-boron bonds are responsible for high mechanical stability. Although W1−x B3 at about 80 at.% B is the metal boride richest in boron, it contains no directly linked three-dimensional boron framework. The solubility of Rh, Ir, Ni, Pd and Pt in W1−x B3 as well as of Rh in Mo1−x B3 has been investigated in as cast state and after annealing. Furthermore, phase equilibria in the boron rich part of the corresponding isothermal sections W-TM-B (TM = Rh, Ir at 1100 °C, TM = Ni, Pd at 900 °C and TM = Pt at 800 °C) and Mo-Rh-B (at 1100 °C) have been established. A ternary compound only forms in the system W-Ir-B: τ1-W1−x Ir x B2 with ReB2 structure type (space group P63/mmc; a = 0.2900, c = 0.7475 nm). The type of formation and crystal structure of diborides W1−x TM x B2 (TM = Ru, Os, Ir) isotypic with ReB2 were studied by x-ray powder diffraction and electron probe microanalysis in as cast state and after annealing at 1500 °C. Accordingly, W0.5Os0.5B2 (a = 0.29127(1), c = 0.7562(1) nm) forms directly from the melt, whereas W0.4Ru0.6B2 (a = 0.29027(1), c = 0.74673(2) nm) and W0.6Ir0.4B2 (a = 0.29263(1), c = 0.75404(8) nm) are incongruently melting. Annealing at 1500 °C leads in case of the iridium compound to an almost single-phase product but the same procedure does not increase the amount of the ruthenium diboride.