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Dive into the research topics where Victor F. Zackay is active.

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Featured researches published by Victor F. Zackay.


Journal of Applied Physics | 1965

Rapid Method for Determining Ternary‐Alloy Phase Diagrams

Kurt Kennedy; Tibor Stefansky; Gordon Davy; Victor F. Zackay; Earl R. Parker

A rapid method for determining isothermal sections of ternary‐alloy diagrams has been developed. Three elements are evaporated simultaneously onto a heated substrate in such a way that the composition of the deposit varies from point to point as it does in a ternary‐phase diagram. An isothermal section of the Fe–Cr–Ni system prepared by the new technique is compared with one reported in the literature. The applicability of this technique to the preparation of ternary phase diagrams is discussed.


Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science | 1972

STABILITY AND MECHANICAL PROPERTIES OF SOME METASTABLE AUSTENITIC STEELS

D. Bhandarkar; Victor F. Zackay; Earl R. Parker

The relation between austenite stability and the tensile properties, as affected by testing temperature and processing, was studied for a series of alloys of increasing compositional complexity, viz., the Fe-Ni, Fe-Ni-C, and Fe-Ni-Cr-Mn-C systems. The “stress” and “strain induced” modes of transformation to martensite differed significantly in their influence on the shape of the stress-strain curve. Under certain testing conditions, unusually low yield strengths and high work hardening rates were observed in some of these alloys. Maxima in yield strengths were observed for all austenitic alloys containing carbon that were processed at deformation temperatures between 200° and 300°C. Evidence gleaned from electron microscopy and magnetic and mechanical testing suggested that the maxima were due to the formation of carbon atmospheres on dislocations during processing. The influence of austenite stability on the mechanical properties of steels, varied by systematic changes in test temperature (22° to -196°C), composition (8 pct, 12 pct, 16 pct, and 21 pct Ni) and deformation temperature (25° to 450°C), was evaluated quantitatively.


Materials Science and Engineering | 1979

Relations between microstructure and mechanical properties in secondary hardening steels

M.S. Bhat; W.M. Garrison; Victor F. Zackay

Abstract Significant developments in the evolution of secondary hardening steels over the past 75 years are reviewed. It is shown that by the beginning of World War II the key solid state changes responsible for the unusual tempering resistance of secondary hardenning steels were becoming clear. In the two decades following the war transmission electron microscopy provided the high resolution tool needed to study the strengthening mechanisms and apparently intrinsic brittleness of secondary hardening steels. The chemical and microstructural factors known to cause the poor toughness are described and progress made in the last decade to improve the toughness is discussed. In particular, the role of the non-carbide-forming elements is examined. The beneficial and detrimental effects of silicon are described in detail. Finally, the enhancement of toughness that might be achieved from the partial substitution of silicon by aluminum is considered.


Engineering Fracture Mechanics | 1975

Microstructural features affecting fracture toughness of high strength steels

Earl R. Parker; Victor F. Zackay

Abstract The fracture toughness of quenched and tempered steels, such as AISI 4340, AISI 4130 and 300M, can be increased by 50–100% by minor changes in heat treating procedures. Certain microstructural features, particularly blocky ferrite, upper bahnte and twinned martensite plates, are deleterious to fracture toughness. Similarly, the presence of undissolved carbides and sulfide inclusions, which act as crack nuclei, can lower fracture toughness by 25–50%. Other microstructural constituents, such as lower bainte, autotempered martensite, and retained austenite can enhance fracture toughness. By controlling the amounts and distributions of the microstructural constituents, the fracture toughness values of AISI 4340, AISI 4130 and 300M can be raised to the fracture toughness level of 18Ni maraging steel at equivalent values of yield strength.


Engineering Fracture Mechanics | 1973

Enhancement of fracture toughness in high strength steel by microstructural control

Earl R. Parker; Victor F. Zackay

Abstract The development of new alloys with improved mechanical properties has been seriously hampered in the past by the inability of a metallurgist to relate quantitatively the variables of microstructure and fracture toughness. The emergence of a unified theory of fracture toughness in the past decade has done much to alleviate this difficulty. As a consequence of a recent interdisciplinary research effort involving both the disciplines of physical metallurgy and experimental fracture mechanics, we have been able to develop alloys with engineering properties superior to those of commercially available materials. This research has required the creation of new and unusual microstructures, utilizing a variety of thermal and thermomechanical processes. The quantitative relationships of mechanical properties (strength, ductility, work hardening, and fracture toughness) with composition and microstructure are discussed in detail for the newly developed TRIP steels. In the report of another development, it is shown how the fracture toughness of low alloy quenched and tempered steels with yield strengths over 200,000 psi can be improved by as much as 70 per cent by microstructural control. Lastly, the initial results of research on alloys intended for cryogenic service are described. The composition, heat treatment, microstructure and properties of an alloy having more than three times the toughness of the presently used alloys are discussed.


Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science | 1971

Tensile properties of 0.05 to 0.20 Pct C TRIP steels

G. R. Chanani; Victor F. Zackay; Earl R. Parker

The uniaxial tensile properties of a series of TRIP steels of varying carbon contents and processing histories were determined over a wide range of test temperatures. The yield strengths at room temperature varied both with the deformation temperature (over the range 250° to 550°C) and with the carbon content (0.05 to 0.20 pct). Possible reasons for these variations are advanced. For all steels, the −100°C yield strengths were substantially lower than the 100°C yield strengths. The minima and maxima in the yield strengths vs temperatures curves were especially pronounced for the steels processed at the lowest deformation temperatures. Both the rate of work hardening and the elongation were influenced by the strain-induced austenite-to-martensite transformation. The rate of strain hardening and the rate of production of strain-induced martensite (per unit strain) increased with decreasing temperature.


Acta Metallurgica | 1965

SOME SUPERCONDUCTING PROPERTIES OF SEVERAL CARBIDES AND NITRIDES OF THE TRANSITION METALS

Louis E. Toth; Victor F. Zackay; M Wells; J Olson; Earl R. Parker

Abstract Analogous to the transition elements, their solid solutions, and intermetallic compounds, a correlation is shown to exist between the total number of valence electrons and the superconducting critical temperature for transition metal carbides and nitrides crystallizing in the NaCl structure. The critical temperature increases as the total number of valence electrons increases from eight to about ten. A number of experiments were undertaken to substantiate the correlation. The critical temperature of cubic molybdenum carbide (NaCl structure) was found to be 13.0°K. The critical temperature of the two-phase mixtures of cubic and hexagonal molybdenum carbide was found to be dependent upon the relative amounts of the two phases present. This behavior was tentatively explained on the basis of the structural similarities of the two phases. A critical temperature for the hypothetical compound, cubic TaN, of 12–14°K is predicted from the variation of the critical temperature with composition for the cubic solid solutions of TaN and TaC.


Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science | 1976

Isothermal studies of bainitic and martensitic transformations in some low alloy steels

Clyde E. Ericsson; M. S. Bhat; Earl R. Parker; Victor F. Zackay

The transformation kinetics of the upper and lower bainitic reactions were determined for four commercial quenched and tempered steels, AISI 4130, AISI 4140, D6AC and AMS 6416 (300-M). Their chemical compositions are given. The kinetics of the bainite reaction below the martensite start temperature (M/sub s/) was determined.


Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science | 1979

The effect of heat treatment on microstructure and mechanical properties in 52100 steel

R. J. Kar; R. M. Horn; Victor F. Zackay

An investigation was carried out to study the microstructure and mechanical properties of isothermally transformed AISI E 52100 steel. Heal treatments consisting of single and two cycle austenitization followed by isothermal holding resulted in duplex structures of martensite and bainite. In addition, high temperature austenitization led to large amounts of retained austenite at room temperature. Conventional oil quenching treatments were also performed for purposes of comparison. It was found that isothermal holding aboveMs after single cycle austenitization resulted in a microstructure which had strength and toughness properties equivalent to quenched and tempered 52100. The two cycle austenitization treatment followed by isothermal holding led to a doubling of the fracture toughness at equivalent hardness and ultimate tensile strength levels relative to the properties of conventional quenched and tempered 52100 steel. The mechanical stability of retained austenite, present after two cycle austenitization, was examined. Although it was found that the presence of unstable retained austenite was associated with the best combination of strength and toughness, it cannot be unequivocally stated that the retained austenite influenced the mechanical properties.


Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science | 1976

A rapid magnetometric technique to plot isothermal transformation diagrams

B.N.P. Babu; Bhat; Earl R. Parker; Victor F. Zackay

A sensitive magnetic permeability method for rapid determination of isothermal transformation diagrams in steels and iron base alloys is described. The method consists of quenching the sample from an austenitizing temperature to a subcritical temperature in an isothermal bath, and holding it within the magnetic field of an inductor coil. The increase in permeability accompanying austenite decomposition increases the inductance of the coil, and this changes the resonant frequency of the circuit. An automatic continuous recording of the corresponding period provides a convenient and accurate method for following the austenite decomposition of AISI 4340 in the bainite and martensite temperature ranges. This method provides quantitative information on austenite decomposition kinetics within two seconds after the start of quenching.

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Earl R. Parker

University of California

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Kurt Kennedy

University of California

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R. J. Kar

University of California

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B.N.P. Babu

University of Connecticut

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Bhat

University of California

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