Nonsteady thermocapillary mass transfer in the laser alloying of metals

This article examines convective mass transfer of an impurity in a shallow bath of molten metal with allowance for the motion of the fusion front during the laser alloying of metals.Notation r, z, cylindrical coordinates - t time - T_i temperature of the liquid (i=1) and solid (i=2) phases - q(r) absorbed energy flux - k concentration factor - T_m melting point - L heat of fusion - density - _i, _i thermal conductivity and diffusivity - T₀ initial temperature - , absolute and kinematic viscosities of the melt - v_r, v_z projections of the melt velocity on the coordinate axes r and z - p pressure - surface tension Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 56, No. 5, pp. 799–805, May, 1989.     

Preparation and properties of close-packed composite materials

Monodisperse silica particles of about 0.3m diameter are suspended in methacrylate monomer using a carefully selected dispersant. Many steric dispersants are hydrocarbon chains with a reactive end-group. These are not effective as dispersants for silica in moderately polar solvents, such as esters and the methacrylate monomers. Good dispersion was obtained with a methacrylate polymer terminated by a chlorosilane end group. Settling or centrifugation of these unagglomerated dispersions gives well-packed particle beds. Polymerization of the surrounding monomer produces composite materials with high packing fractions and a high degree of regularity. Moduli and strengths of these composites are reported.     

Martensitic transformation in alloys of the system TiNi-TiCu prepared by ultrarapid melt cooling

Conclusion In alloys of the TiNi-TiCu system prepared in the form of thin tapes by ultrarapid melt cooling the B2-phase, which is unstable towards martensitic transformation B2B19, contains up to 35% Cu, whereas in bulk alloys prepared in the form of an ingot cooled at normal rates it contains about 10% Cu close to the M_S. In alloys containing up to 35% Cu there are no untransformed brittle phases preventing development of martensitic transformation throughout the volume of the material. The structure of alloys is quite uniform, particularly those obtained by crystallizing from the amorphous condition, and the grain size of the high-temperature phase is a fraction of a micron. The fine structure of alloys close to a globular at a high cooling rate. Thus, range of practically important alloys of the B2 type with inelastic behavior effects, e.g., the shape memory effect, is considerably expanded.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 38–41, November, 1988.     

Determining the mechanical characteristics of soils from static-penetration data

Conclusion 1. For clayey soils, it is possible to confirm, using the curves in Fig. 2, the interlinking of the resultant data from the results of penetration and laboratory determinations of the compression modulus and the undrained-shear strength.2. For sandy soils, it is possible to determine with reliability the angle from Fig. 3 for different penetration depths and different values of q.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 28–30, January–February, 1978.     

Averaging the sinter charge in hoppers

Zaporozhe Industrial Institute. Zaporozhstal' Combine. Translated from Metallurg, No. 2, pp. 19–21, February, 1988.