C. M. Craighead

Constitution and mechanical properties of titanium-hydrogen alloys

Hydrogen forms a beta-stabilized system with titanium, with a beta eutectoid at about 300°C and 44 atomic pct H2. The solid solubility of hydrogen in alpha decreases from about 8 to about 0.1 atomic pct from 300°C to room temperature. Hydrogen has little effect on tensile properties, but decreases notch-bar toughness to a large degree. This latter effect appears to be the result of increased notch sensitivity.

Titanium binary alloys

Binary alloys of titanium with silver, lead, tin, nickel, copper, beryllium, boron, silicon, chromium, molybdenum, manganese, vanadium, iron, and cobalt were studied. One-half-pound ingots of the alloys were prepared in an arc furnace, employing a water-cooled copper crucible, an argon atmosphere, and a water-cooled tungsten electrode. The half-pound ingots were fabricated by forging at 1700°F in air to 1/4-in. slab, followed by hot rolling at 1450°F to 0.060-in. sheet. Tensile properties, minimum bend radii, hardnesses, response to heat treatment and aging treatment, and phase relationships were determined for these alloys.

Physical and Mechanical Properties of Rhenium

The fabrication of rhenium metal by powder metallurgy techniques is discussed. The following physical and mechanical properties have been measured and are reported: lattice constants, melting point, electrical resistivity, thermal expansion, spectral emissivity, modulus of elasticity, tensile properties and ductility at room and elevated temperatures, work hardening, recrystallization, grain growth, and oxidation resistance.

Ternary Alloys of Titanium

The results of a preliminary study of 113 ternary titanium-base alloys are described. The compositions investigated were as follows: Tensile properties, minimum bend radii, hardnesses, response to heat treatment and aging treatment, and phase relationships for these alloys were determined.

Hydrogen Embrittlement of Beta-Stabilized Titanium Alloys

The α-β type alloys are subject to a loss of tensile ductility with increasing hydrogen content. No hydride phase is visible in embrittled α-β type alloys. The embrittlement encountered appeared to be of the strain-aging type. Both compositional and structural factors are shown to influence the hydrogen tolerance of α-β type alloys.

Effect of Testing Variables on the Hydrogen Embrittlement of Titanium and a Ti-8 pct Mn Alloy

The effects of increasing hydrogen content, introducing a notch, and changing the strain rate on properties of titanium and one of its alloys were investigated over a range of testing temperatures from —196° to 200°C. Both high purity and commercial purity A-55 titanium were used as representative a materials, while a commercial Ti-8 pct Mn alloy was used for an α-β alloy. It was found possible to analyze the data, using the ductile-to-brittle transition temperature concept. Increasing hydrogen, the presence of a notch, and increasing the testing speed raised the transition temperature for the a materials. The presence of hydrogen and notches raised the transition temperature of the α-β alloy also. However, increasing the testing speed generally decreased the transition temperature of the α-β alloy.

Quaternary alloys of titanium

Eighty-four quaternary titanium-base alloys from the following systems were investigated: The tensile properties, minimum bend radii, hardnesses, response to heat treatment and aging treatment, and phase relationships of these alloys are reported.