Balti Research Articles

Book reviews : Dorn, H. 1991: The geography of science. Balti more and London: The John Hopkins University Press. xx+220 pp. £26.00 cloth. ISBN: 0 801 84151 8

Book reviews : Dorn, H. 1991: The geography of science. Balti more and London: The John Hopkins University Press. xx+220 pp. £26.00 cloth. ISBN: 0 801 84151 8

Effects of combined high and low temperature deformation processing of β III titanium

The structure and properties of β III titanium alloy (nominal composition: 11.5 pct Mo, 6 pct Zr, 4.5 pct Sn, bal Ti) were studied as a function of combined high and low temperature ther-momechanical processing. A water quenched extrusion was deformed various amounts by swaging at room temperature prior to the aging treatment. No re-solution heat treatment was employed. The swaging introduced mechanical twinning and a small amount of stress induced orthorhombic martensite. Following a 900°F, 8 hr aging treatment, substantial increases in yield and tensile strength were observed, combined with a severe decrease in tensile ductility in samples with small amounts of swaging. The orientation and morphology of the deformation products have a critical influence on tensile ductility. A decrease in the plane strain fracture toughness accompanied the large increase in tensile strength.

Moire Fringes in Alpha Plates Within a Beta Titanium Alloy

When the beta phase isothermally transforms to alpha upon aging, the lenticular alpha precipitate frequently exhibits fine parallel markings, as shown in Figure 1, but the nature of the markings remains unexplained, although microtwins and oxide epitaxy have been suggested. Therefore, 25μ thick foil specimens of the alloy (14.0V, 11.5 Cr, 3.2 Al, bal Ti) were solution annealed 1/4 hr. at 788C, and aged 24 and 72 hr. respectively at 482C — using a predessicated Argon atmosphere. The heat-treated foils were electrolytically thinned in a 6% perchloric acid, 59% methanol, 35% ethylene glycol monobutyl ether electrolyte, at 15-18 volts, using a Bollmann electrode arrangement.Because of the absence of twin reflections and the lack of evidence of an oxide film by electron diffraction from foils exhibiting parallel markings in the alpha plates (Figure 1), the markings were suspected to be Moiré fringes produced by double diffraction from the alpha precipitate and the beta matrix respectively.

DICKINSON, HOBART C. The Mechanics of Prosperity. Pp. xvi, 136. Balti more : Williams and Wilkins Company, 1937. $2.00

DICKINSON, HOBART C. The Mechanics of Prosperity. Pp. xvi, 136. Balti more : Williams and Wilkins Company, 1937. $2.00