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Work strengthening and microstructure were investigated for a class of alloys, designated “MP Alloys”, containing 20 pct Cr, 10 pct Mo, and the remainder cobalt and nickel in proportions ranging from 60Co∶10Ni to 30Co∶40Ni. These alloys, in the fully annealed, homogenized condition, have a fcc structure with yield strengths ranging from about 45 to 60 ksi. Deformation at room temperature rapidly increases the yield strength of the alloys to about 250 ksi. Structural analyses by X-ray and electron diffraction techniques indicate that this marked increase in strength is associated with a deformation-induced martensitic transformation forming a network of extremely thin hcp platelets within the fcc grains. The nature of this martensitic transformation was studied as a function of alloy composition, deformation temperature, and structural variables, such as the platelet size, thec/a ratio of the hcp phase, and twinning.

Values of the interface roughness parameter (α) have been calculated for the primary phases of the 12 simple binary eutectic systems for which sufficient thermodynamic data are available; namely, Ag−Bi, Ag−Cu, Ag−Pb, Al−Ge, Al−Sn, Bi−Cd, Bi−Sn, Cd−Pb, Cd−Zn, In−Zn, Pb−Sb and Sn−Zn. It is shown that in the presence of solute the values of α can be significantly different from those of the pure component elements. The calculated, values of α are correlated with eutectic morphologies on the basis of the Hunt and Jackson classification. If the broken lamellar structure is also in the faceted/nonfaceted group then the results are in agreement with Hunt and Jackson’s classification. The analysis is discussed in the light of recent interpretations of the theories of solid-liquid interfaces and resultant growth morphologies. It is concluded that thermodynamic calculations are useful in the prediction of eutectic structures even though they may not necessarily resolve arguments concerning the mechanisms of eutectic solidification.

A method utilizing textural symmetry is described for establishing the defocusing correction in the Schulz reflection technique of pole figure analysis. An offset specimen is necessary for this determination and sample material identical to that under study is used. This avoids certain difficulties associated with the conventional textureless specimen procedure. The new method is compared with the earlier method in studies of copper, and changes in the defocusing function with receiver slit width and Bragg angle are evaluated. Factors affecting the choice of specimen orientation are examined for the case of orthotropic symmetry.

The diffusion of liquid copper in iron from a notched surface has been studied by metallographic, microanalysis, and sessile drop techniques. The diffusivity of copper was found to be 0.59×10−6 sq cm per sec at 1100°C and 0.97×10−6 sq cm per sec at 1130°C. The diffusion factor,D 0 was 0.78×10−3 sq cm per sec and the activation energy 19.0 kcal per mole. The predominant mode of copper penetration was along grain boundaries, but when larger volumes of copper at the iron surface were used, surface diffusion increased and grain boundary penetration remained constant. The most frequently occurring dihedral angle for liquid copper was 34 deg at 1100° and 1130°C. The liquid copper/austenite interfacial energy was found to be 444 ergs per sq cm between 1100 and 1130°C. From sessile drop measurements, the contact angle was determined as 35 deg at 1100°C and 28 deg at 1130°C, from which values the respective interfacial energies were calculated to be 387 ergs per sq cm and 301 ergs per sq cm.

The microstructure of a ternary alloy, Al-5 wt pct Ti, 1 wt pct B, has been examined by optical and electron transmission microscopy, by selected area diffraction, and electron probe microscopy, by selected area diffraction, and electron probe microanalysis. Particles of Al3Ti are found at the center of grains and there exist preferred epitaxial orientations between this compound and the surrounding aluminum. Particles containing titanium and boron occur at aluminum grain boundaries and have no preferred configurations with respect to the aluminum or to one another. It is concluded that the active heterogeneous nuclei are therefore Al3Ti and that particles of TiB2, AlB2, or a ternary compound are not active in this alloy. Grain size measurements in binary Al-Ti alloys suggest that particles of a nucleating phase must be present at concentrations as low as 0.01 wt pct Ti, and it is suggested that these could be Al3Ti if the existing binary phase diagram Al-Ti is in error.

The origin of “extra” spots in electron diffraction patterns taken from retained austenite and martensite in Fe-7 pct Al-2 pct C has been investigated. The present interpretation differs from that of previous investigators. It is concluded that a high density of fine carbide precipitates 50Å in diameter is responsible for the extra reflections. The precipitates have the perovskite structure and grow epitaxially in the austenite during quenching. When martensite forms at a lower temperature, the precipitates are transformedin situ.

An approximate analysis is presented to describe the flow field in molten steel held in a ladle, as caused by natural convection. It is shown that a thick (say 8 to 14 in.) slag layer is required to suppress extensive vertical mixing within the ladle. It is also shown that natural convection caused by the contact of the metal with the cold ladle walls may produce mass flow rates of the order of 2 to 3 tons per min for typical 100 to 150 ton ladles. If ladles are tapped at comparable rates, then this pehnomenon can effectively prevent mixing in the bulk. The resultant stratification may be desirable in tundish temperature control.