William J. Buehler

Effect of Low‐Temperature Phase Changes on the Mechanical Properties of Alloys near Composition TiNi

X‐ray diffraction and dilation studies have shown that alloys near the stoichiometric TiNi composition undergo transformation into the related phases Ti2Ni and TiNi3 at low temperatures. The main factors controlling these phase transformations are alloy composition, temperature, and mode of plastic deformation. In plastic deformation, tensile or compressive stressing produced separate and unlike decomposition phases; this finding was dramatically demonstrated by unique temperature‐sensitive dimensional changes in plastically deformed specimens. Changes of large magnitude in vibration damping have also been noted and appear related to variations in the phase equilibria of the system.

A summary of recent research on the nitinol alloys and their potential application in ocean engineering

Abstract The Nitinol alloys are based on the intermetallic compound TiNi. Alloys on the nickel-rich side of stoichiometry contain a certain portion of the compound TiNi3 in equilibrium with TiNi and are hardenable. In other alloying variations some of the nickel is replaced with cobalt. When a near stoichiometric specimen is mechanically deformed below its martensitic transition temperature it retains this deformed shape indefinitely. Upon heating above its martensitic transition temperature, however, it rapidly reverts to the shape it had before deformation. Thus the material exhibits a “mechanical memory” effect. The martensitic transition temperature may be varied within wide limits by changing the composition of the alloy. Cobalt, in the formula TiNixCo1−x, is an effective substitution element for lowering the transition temperature. The resistance of some of the Nitinol alloys to corrosion in sea water has been evaluated by conducting high velocity impingement, cavitation-erosion, stress corrosion and crevice corrosion measurements. The results of these tests have shown these alloys to be quite resistant to marine corrosion. Combination of the unusual mechanical and corrosion properties exhibited by these alloys make them especially suitable for applications in ocean engineering.

16 Percent Aluminum‐Iron Alloy Cold Rolled in the Order‐Disorder Temperature Range

The methods of fabricating 16 percent Al‐Fe from cast slab to thin‐gauge sheet are described in some detail. The melting, casting, homogenizing, hot rolling, and cold rolling at 575°C and room temperature are described. Particular attention is focused upon the 575°C cold rolling from the standpoint of the possible beneficial effects derived from an ordering reaction which occurs in this alloy. The technique of cold reduction from 0.007 in. to 0.0005 in. at room temperature is discussed.Magnetic data on a limited number of heat‐treated laminated cores are given. Useful physical properties, other than magnetic, of previous limited interest because of the inability to fabricate the alloy into ductile strong thin sheets, are discussed. These properties include excellent oxidation resistance at high temperatures, good wet‐corrosion resistance to certain chemical solutions, and high electrical resistivity.