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[en] A very simple atomistic model for predicting the heats of formation of alloys involving transition elements is presented. Because of the paucity of experimental thermodynamic data, the sign of the heat of formation was determined from the known behaviour of the binary phase diagrams. By assigning only two co-ordinates to each transition element, it was found that all those binary alloys with positive heats of formation could be separated from those with negative values. By fixing the magnitude of the heat of formation to known experimental values, it was possible to predict values for all those binary systems which had not yet been measured. This work is invaluable because it not only tabulates the predicted heats of formation of binary compounds involving transition elements, but it also updates Hultgren's 1973 compilation of the experimental thermodynamic data. Moreover, the collation of all binary T-X phase diagrams containing a given transition element T with respect to X's period and group will be very useful for providing a global view of trends across the periodic table. refs.; figs.; tabs
[en] A method of calculating γ phase compositions in Ni-base superalloys is described in which the volume fraction of γ' obtained using a regression equation is refined using an iteration procedure and the refined value is then used to compute the γ and γ' compositions using further regression equations. The method is applied to heats of Udimet 700 and In 738. Resulting data are tabulated and analyzed
[en] The influence of the addition of third elements into permalloy films on anisotropic magnetoresistance (AMR) has been investigated for a large number of third elements. AMR decreases rapidly for the addition of Sc, Ti, V, Cr, Ge, Zr, Nb, Mo, Ru, Ta and W. On the other hand, the decreases in AMR are relatively slow for the addition of Co, Cu, Pd, Ag, Pt and Au. We have found the tendency that the influence of the elements which are situated near Ni in the periodic table is smaller than that of the elements which are situated far from Ni
[en] In this work, a multilayered perceptron (MLP) network is used to develop predictive isothermal time-temperature-transformation (TTT) models covering a range of U-Mo binary and ternary alloys. The selected ternary alloys for model development are U-Mo-Ru, U-Mo-Nb, U-Mo-Zr, U-Mo-Cr, and U-Mo-Re. These model's ability to predict 'novel' U-Mo alloys is shown quite well despite the discrepancies between literature sources for similar alloys which likely arise from different thermal-mechanical processing conditions. These models are developed with the primary purpose of informing experimental decisions. Additional experimental insight is necessary in order to reduce the number of experiments required to isolate ideal alloys. These models allow test planners to evaluate areas of experimental interest; once initial tests are conducted, the model can be updated and further improve follow-on testing decisions. The model also improves analysis capabilities by reducing the number of data points necessary from any particular test. For example, if one or two isotherms are measured during a test, the model can construct the rest of the TTT curve over a wide range of temperature and time. This modeling capability reduces the cost of experiments while also improving the value of the results from the tests. The reduced costs could result in improved material characterization and therefore improved fundamental understanding of TTT dynamics. As additional understanding of phenomena driving TTTs is acquired, this type of MLP model can be used to populate unknowns (such as material impurity and other thermal mechanical properties) from past literature sources.