Physical Metallurgy Citations
Exploratory Study of
Elevated Temperature Tensile Properties of Alloys Based on the
Intermetallic Compound TiNi
M. Garfinkle; Metallurgical
Transactions; 5 (1974) 2383
An Electrochemical Model of Hot-Salt Stress-Corrosion of Titanium Alloys M. Garfinkle; Metallurgical Transactions; 4 (1973) 1677
ABSTRACT - The tensile properties and oxygen contamination behavior of TiNi and several of its alloys were examined in the temperature range between 800 and 1000 K (980 and 1340°F). Additions of aluminum, chromium and silicon increased the elevated temperature tensile strength of TiNi up to threefold. TiNi and its alloys are less susceptible to elevated temperature oxygen contamination than is the Ti-6242 alloy. The elevated temperature tensile strength of TiNi is not affected by the 900 K (1160°F) allotropic transformation. Aluminum and possibly chromium promote solid-solution softening in TiNi at low solute concentrations.
Effect of Rhenium Alloying on Lattice Dilation of the Group VI-A refractory Metals M. Garfinkle; Metallurgical Transactions; 1 (1970) 1062
ABSTRACT - An electrochemical model of hot-salt stress-corrosion cracking of titanium alloys is proposed to correlate the diverse observations mad concerning this process. According to the model an oxygen-concentration cell exists between the exposed surface of the corrosion specimen and shielded areas, such as under salt crystals and at crack tips. Oxygen is reduced at the exposed cathode regions while substrate dissolution occurs at the shielded anodes with formation of complex halides. The hydrolysis of these halides is the source of hydrogen that subsequently imbrittles the substrate. The model is consistent with observations made concerning the distribution of various ions and absorbed hydrogen in the vicinity of stress-corrosion cracks. The model is also consistent with the effects of salt composition and various surface additives on the susceptibility to stress-corrosion cracking as well as the effects of alloying and coatings.
Superplasticity in Tungsten-Rhenium Alloys M. Garfinkle, W.R. Witzke, W.D. Klopp; Trans. Metall. Soc. of AIME; 245 (1969)303
ABSTRACT - In view of the anomalous effects of large rhenium additions on the room temperature ductility of the Group VI-A elements, chromium, molybdenum and tungsten, it is of interest to consider whether or not unusual lattice may be present that might contribute to this effect.
A Stereographic Representation of Knoop Hardness Anisotropy M. Garfinkle, R.G. Garlick; Trans. Metall. Soc. of AIME; 242 (1968) 809
ABSTRACT - The tensile properties of binary W-Re alloys containing up to 33 at. pct Re were determined at temperatures from 78°F to 3630°F. Elongations as high as 260 pct were observed in electron-beam melted tungsten containing 23 at. pct Re when tensile tested at 3630°F after a one hour anneal at 3090°F. All alloys tested under these conditions with rhenium contents between 20 and 28 at. pct exhibited elongations of at least 200 pct. These alloys also showed enhanced grain growth rates. The value of strain-rate sensitivity ranged between 0.2 and 0.3 for the alloys exhibiting high elongations. However, for swaged alloys tested just above the recrystallization temperature, strain-rate sensivities as high as 0.8 were observed. The high-temperature stength of the high-rhenium-content alloys were also less than those of alloys with intermediate rhenium contents.
Proportional-Limit Stress of Tungsten Single Crystals M. Garfinkle; Trans. Metall. Soc. of AIME; 236 (1966) 1373
ABSTRACT - It was observed for several bcc metal crystals that the Knoop Knoop hardness anisotropy was dependent essentially on the direction of the long axis of the indentor alone and not on the plane of indentation. The generality of this observation was tested for an fcc and an hcp metal and an ionic crystal. For cubic crystals this observation was valid, for the hcp structure however the plane on indentation did have an effect on the hardness anisotropy, although this was not nearly as significant as the direction of indentation. Because the direction of indentation is the only significant crystallographic parameter necessary to to describe the hardness anisotropy, it is possible to represent the anisotropy of single crystals on the standard stereographic triangle.
Reaction of Liquid Titanium with Some Refractory Compounds M. Garfinkle, H.M. Davis; Trans. ASM; 58 (1965) 520
ABSTRACT - Literature data have suggested that the resolved shear stress necessary to initiate slip in a particular slip system in tungsten single crystals is strongly dependent on the tensile orientation of crystals. This orientation dependence is contrary to the critical resolved shear stress criterion. However precise strain measurements indicate that the critical resolved shear stress criterion for slip initiation is applicable to tungsten crystals, at least for the <100> and <110> orientations.
ABSTRACT - The reaction of liquid titanium with various nonmetallic refractory substances was investigator by observation of the melting behavior of titanium blocks in contact with polished plaques of the ceramic materials. After reaction the metal-ceramic interface was investigated by metallographic techniques, with the aid of hardness measurements, and with the id of the electron-probe microanalyser. The principal mechanisms of attack were
- 1) simple dissolution of the plaque,
- 2) melting of an intermediate phase, and
- 3) eutectic reaction between the titanium block and an intermediate phase.
The materials tested were carbides, borides, a silicide, and a sulphide.
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