Progress made in applying advanced techniques and structural concepts to the problem of strengthening the Group VI-A metals, Cr, Mo, and W, is examined. At low temperatures, T/Tm

This report supplements DMIC Report 152 which is a compilation of binary and ternary phase diagrams of columbium, molybdenum, tantalum, and tungsten. Forty new binary and 80 new ternary diagrams are included, some of these being revised versions of the previously published diagrams. Included with each binary diagram and with some ternary diagrams is a short discussion listing terminal solubilities and crystal struc tures of intermediate pahses. Many of the diagrams are tentative and are subject to revision as additional data become available. (Author).

This report summarizes information on refractory composites for use above 2500 F, as presented at the Seventh Meeting of the Refractory Composites Working Group, held March 12-14, 1963. Reports presented at the meeting were concerned with pro tective coatings, insulating ceramics, materials for rocket thrust chambers, dispersion strength ening of metals, joining of refractory materials, and testing techniques. Emphasis in the field of coatings for refractory metals has shifted from the rudiments of developing oxidation-resistant coatings to improvement and advanced evaluation of coatings to predict their utility for re-entry vehicles. (Author).

The Nb program is nearing completion of laboratory tory rolling studiory materials, *Heat resistant alloys, *Sheets, Niobium alloys, Molybdenum alloys, Tantalum alloys, Tungsten alloys, Titanium alloys, Zirconium alloys, Tungsten, Powder metallurgy, Electric arcs, Manufacturing methods, Mechanical proper ies, Forging, Heat treatment, Melting, Extrusion, Deformation, Hardness, Rolling mills, Processing. Identifiers: Floturning. The Nb program is nearing completion of laboratory tory rolling studies, and a single composition for larger scale rolling studies will be selected in the near future. In the Mo program, it has been shown that true hot forging of billets to sheet bar results in higher recrystallization temperatures of TZM and Mo-0.5Ti sheet than are obtained when normal forging temperatures are used. The Ta program is in the early stages of ingot production and primary breakdown fabrication of the Ta-30Nb-7.5V alloy. Three methods of fabricating W sheet are being investigated: rolling of powder-metallurgy billets, fabrication of arc-melted ingots, and floturning of cylindrical blanks. Properties obtained on both powdermetallurgy and arc-melted tungsten sheet compare very favorably. Evaluation of the formability of Mo-alloy sheet has been delayed until sheet is available from the production program. (Author).

Reports of Government-supported research on the physical and process metallurgy of beryllium that were received at DMIC during the period 1958-1960, inclusive, are summarized, together with some reports and publications of foreign authors. No proprietary or classified information is included. In addition, reference is made to some of the more importa t writings on health hazards and safety procedures that appeared during the period covered. (Author).

The effect of fast-neutron (>1 Mev) irradiation on the mechanical properties of structural metals and alloys was studied. Although the yield strengths and ultimate tensile strengths are increased su stantially for most materials, the ductility suffers severe decreases. This report presents these changes in properties of several structural metals for a number of neutron exposures within the 1.0 x 10 to the 18th power to 5.0 x 10 to the 21st power n/sq cm range. Data summarizing these effects on several classes of materials such as carbon steels, low-alloy steels, stainless steels, Zr-base alloys, ni-base alloys, Al-base alloys, and Ta are given. Additional data which show the influence f irradiation temperatures and of post-irradiation annealing on the radiation-induced property changes are also given and discussed. Increases as great as 175% in yield strength, 100% in ultimate strength, and decreases of 80% in total elongation are reported for fast-neutron exposures as great as 5 10 to the 21st power n/sq cm. (Author).