The liquidus surface of the system titanium-copper-silver

Conclusions The liquidus surface of the system titanium-copper-silver was studied by metallographic and thermal analysis methods. Projections were constructed of liquidus surface isotherms on the plane of the concentration triangle, and the shape of the simultaneous-crystallization curves of various phases (boundary curves) was determined.Translated from Poroshkovaya Metallurgiya, No. 4 (88), pp. 44–48, April, 1970.     

The liquidus surface and tie-lines in the iron-nickel-sulfur system between 1473 and 1673 K

The liquidus compositions and the tie-lines for the solid alloy plus liquid sulfide two-phase region were determined for the iron-nickel-sulfur system in the temperature range 1473 to 1673 K. Experiments were conducted by sampling the liquid sulfide in equilibrium with the alloy phase and chemically analyzing the sulfide. The alloy was quenched and analyzed by electron microprobe. The results represent a significant revision to existing data.     

The liquidus surface and tie-lines in the iron-cobalt-sulfur system between 1473 and 1623 K

The liquidus surface and tie-lines in the iron-cobalt-sulfur ternary system have been determined between 1473 and 1623 K. The experiments were conducted by equilibrating the liquid sulfide phase with the metallic alloy phase. The liquid sulfide phase was sampled and chemically analyzed. The alloy phase was analyzed by electron microprobe. Combining the present results with the available literature data, the thermodynamic properties of this system were calculated.     

The liquidus surface and tie-lines in the iron-nickel-sulfur system between 1473 and 1673 K

The liquidus compositions and the tie-lines for the solid alloy plus liquid sulfide two-phase region were determined for the iron-nickel-sulfur system in the temperature range 1473 to 1673 K. Experiments were conducted by sampling the liquid sulfide in equilibrium with the alloy phase and chemically analyzing the sulfide. The alloy was quenched and analyzed by electron microprobe. The results represent a significant revision to existing data.     

The Fe-rich corner of the metastable C-Cr-Fe liquidus surface

The liquidus surface of the C-Cr-Fe system has been experimentally determined in the Fe-rich region —C ≤6 wt pct, Cr ≤40 wt pct —using a sensitive differential thermal analysis technique, along with optical and scanning electron microscopy and X-ray diffraction. Previous liquidus surfaces for this system have differed on the extent of the (Cr,Fe)₂₃C₆ liquidus field, with one version reporting its existence at ∼20 wt pet Cr, and others finding that it did not occur at Cr levels of less than ∼60 wt pct. The present investigation provides evidence in favor of the second contention, with the (Cr,Fe)₂₃C₆ field not being detected at Cr ≤40 wt pct. Changes are proposed to the accepted liquidus surface in respect of the compositions of the invariant reactions—L + αδFe ⇌γFe + (Cr,Fe)₇C₃ andL + (Cr,Fe)₇C₃ ⇌γFe + (Fe,Cr)₃C —and of the monovariant eutectic valley—L⇌ γFe + (Cr,Fe)₇C₃.     

Investigation of the surface of the liquidus of the Fe-Ni-S system at X s<0.51

Methods of thermal analysis, X-ray, optical, and electron microscopy were used to study the liquidus surface of the Fe-Ni-S system in the field of 35 to 51 at. pct sulfur. The FeS-NiS, FeS-Ni₃S₂, Fe_0.55S_0.45-Ni_0.55S_0.45, and Fe_0.61S_0.39-Ni_0.61S_0.39 sections and some additional samples were examined. A microscopic study of the samples slowly cooled and annealed enabled referring of all the samples to the fields of primary crystallization of the monosulfide solid solution (Fe _x Ni_1−x )S_1+y (MSS), the Fe-Ni solid solution with the γ-Fe structure (TN), and the (Fe _x Ni_1−x )_3±y S₂ heazlewoodite solid solution (HZSS). The data, obtained by a method of derivative thermal analysis, have been used to describe analytically the MSS and HZSS surface of primary crystallization. Previous results were used together with our own data to construct the TN surface of primary crystallization. These parts of the liquidus surface have been approximated by polynomial equations, the coefficients of which were determined by the least-squares method. As a result of the absence of experimental data in the δ-Fe-based solid-solution primary crystallization field, this liquidus part is approximated on the basis of the Fe-S and Ni-Fe phase diagram data. The equations are used to construct the boundaries between various areas of phase primary crystallization, to define the coordinates of a triple point, and to construct isotherms.     

Calculation of the liquidus of the Mo-C system

Conclusions Existing data on the Mo-C system make it possible to construct a consistent system of models of thermodynamic properties of phases. To obtain satisfactory agreement between calculated phase equilibrium lines and experimental results, it is necessary to allow for the solubility of carbon in molybdenum. The system of phase models enables the parameters of low-temperature solid-state transformations (in particular MoC formation) to be estimated.Translated from Poroshkovaya Metallurgiya, No. 4(268), pp. 37–42, April, 1985.     

Effects of liquidus and solidus curvature in solidification modeling of binary systems with constant partition ratio

A microsegregation model is used to investigate the effect of approximating liquidus and solidus lines in binary phase diagrams by straight lines during solidification modeling. Even if repartitioning of solute can be described by a constant partition coefficient, the curvature of the phase boundary lines exerts an influence on results of microsegregation calculations. Deviations of liquids and solidus lines from linearity have a distinct influence on microstructural parameters predicted for a wide range of cooling conditions, owing to the effect of pronounced changes of the solidified fraction at a given temperature. Results obtained with simplified phase diagrams should therefore be considered with care.     

Approximation of the liquidus surface of the HfO2-Y2O3-CaO system by reduced polynomials

Translated from Poroshkovaya Metallurgiya, No. 12, pp. 50–55, December, 1990.     

Rapid melting and solidification of a surface layer

Metallurgical and Materials Transactions B - A one-dimensional computer heat flow model is used to investigate the effect of high intensity heat fluxes,e.g. those achieved via continuous CO2 laser...     

Rapid melting and solidification of a surface layer

A one-dimensional computer heat flow model is used to investigate the effect of high intensity heat fluxes,e.g. those achieved via continuous CO2 laser radiation, on the important surface layer melting and subsequent solidification variables of three substrate materials: aluminum, iron, and nickel. Temperature profilesvs time, melting, and solidification interface velocities, heating, and cooling rates in the surface layers of the three metals are calculated. Results are presented in a general form to permit determination of these variables for large ranges of absorbed heat fluxes and times. General trends established show that temperature gradients in the liquid and solid phases and interface velocities are directly proportional to the absorbed heat flux, whereas melt depth is inversely proportional to the absorbed heat flux. Average cooling rates comparable to splat cooling can be achieved by increasing the heat flux and reducing the dwell time of the incident radiation. An order of magnitude increase in the absorbed heat flux results in a corresponding two orders of magnitude increase in average cooling rates in the liquid during solidification of crystalline and noncrystalline structures. Formerly Research Associate, Formerly Research Associate, Formerly Research Associate,     

Directional solidification and phase equilibria in the Ni-Al system

A method for the optimization of a phase diagram on the basis of results from directional solidification experiments is proposed. The experimental microstructure selection map is compared with a calculated map and the input parameters are varied until a satisfactory agreement is obtained. The calculation of the microstructure selection map is based on the maximum temperature criterion and on analytical models for the growth of plane front, dendritic, and eutectic structures. This method is applied to the Ni-Al system where the phase equilibria close to the melting point of the γ′-Ni₃Al phase have been subject to discussion for over 50 years. A new version of this part of the phase diagram is proposed, which is coherent with the results from directional solidification experiments.     

Liquidus surface and solidification scheme for alloys of the system Ti-Ni-Zr containing up to 50% Ni

Translated from Poroshkovaya Metallurgiya, No. 8(344), pp. 49–54, August, 1991.