tailieunhanh - Modeling and Simulation for Material Selection and Mechanical Design Part 4

Tham khảo tài liệu 'modeling and simulation for material selection and mechanical design part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Table 1 Composition at. of the Fe-P and Fe-P-Mo Alloys Chemical composition at. C S P Mo 0 0 0 bulk and on the interface. As seen in Fig. 14 the elastic interaction energy of the P atoms with grain boundaries in iron is equal to at and decreases significantly at molybdenum alloying to at in the alloy . Mo. Decrease of segregation energy of the impurity at its Figure 14 Change of Eseg of phosphorus with its volume concentration in Fe 1 and at. Mo-P alloys 2 . Auger electron spectroscopy of free surface segregations at 823K. Copyright 2004 by Marcel Dekker Inc. All Rights Reserved. volume concentration growth is caused by chemical pair interaction of the atoms in alloy. Using the example of the Fe-P system we could determine chemical interaction of elements by applying the approach proposed in Ref. 34 . Analyzing the solidus and liquidus equilibrium volume and GB on the equilibrium phase diagram at three temperatures permits the construction of a system of three equations that describe this equilibrium kTqa - ln 100 x x2W - x2w kqaTa 17 V 100 - xj s l qa v where k is the Boltzmann constant Ta is the melting temperature of Fe qa is melting entropy per atom divided by Boltzmann constant W0 and W00 are the mixing energies in solid and liquid states Xs and Xl are the impurity concentration in solid and liquid phases at the temperature T. Solving these equations for the phase diagram of Fe-P binary system 35 the sign and value of mixing energy in liquid phase equal eV at were determined. The positive value in accordance with physical sense means that binding force of P-P and Fe-Fe atoms is higher than for Fe-P atoms W WFe-P - 1 WFe-Fe Wp_p 18 emphasizing the tendency for solid solution tendency for stratification or intercrystalline internal adsorption. D. Effect of Solute Interaction in