Three grades of unalloyed titanium were studied to determine the effect of variations in O and N contents on delayed cracking. The bar stock was analyzed for interstitial content, then vacuum annealed to remove most of the H. Large samples of the 1/2-in.-diam vaccum-annealed stock were subsequently hydrogenated to about 90 and 160 ppm H levels. Hydrogen-induced strainaging embrittlement at ambient temperatures in interstitial-containing alphi Ti was not indicated by the results of stress-rupture tests. The results indicate that strain-aging embrittlement does not occur in unalloyed Ti having up to 0.38 wt-% O with as much as 160 ppm H content. However, a noticable effect of H on notch sensitivity of the materials, in the alpha-annealed and especially in the beta-annealed conditions, was observed. It appears probable that H was concentrated in the critical areas by a thermaldiffusion process to create an ultrasensitive zone. Failure might have occurred subsequently as a result of simple overstressing, or by accidentally applied impact stresses, or by a more complicated low-cycle fatigue mechanism. (Author).

Reported progress on the electron-beam welding of commercially pure W indicates that sound crack-free welds can be made if the weld is not restrained during welding. Although the data are not all consistent, welds which are smooth and have minimum fusion and heat-affected zone width should be the strongest and most ductile. Tensile strengths are equivalent to the base metal near the recrystallization temperature but are appreciably lower at room temperature. The ductile-to-brittle transition temperatures for electron-beam-welded tungsten are above that of the base metal. The impact resistance of electron-beam-welded tungsten is very low. Electron-beam welding of tungsten parts should be thoroughly evaluated on production prototypes before specifying its use. (Author).

Research and development in the field of high-strength stainless steels appears to be directed along two principal paths: (1) the development of alloys with improved strength properties and (2) the accumulation of information on the properties and physical metallurgy of existing alloys so that they may be used more effectively. By and large, the development of new alloys is being carried out by the stainless-steel producers, while the accumulation of property data for the most part is being undertaken on Government contracts. (Author).

A brief review is presented of progress in the development of Mg-Li-base alloys. By virtue of the Li, which has a specific gravity of 0.53, they have lower densities than any commercial Mg alloy. Li markedly improves the ductility and workability of magnesium. Since they have approximately the same modulus of elasticity as Mg alloys, about 6.5 million psi, the alloys have a high ratio of elastic modulus to weight, making possible rigid, light structures. No Mg-Li alloys are in commercial production. (Author).