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Title: THE PRINCIPLES OF DISPERSION HARDENING WHICH PROMOTE HIGH-TEMPERATURE STRENGTH IN IRON-BASE ALLOYS. Period Covered: March 1, 1957 to February 29, 1958

Abstract

Eleven alloys, based on iron--18% chromium, were prepared with up to 16% nickel so that the alpha -, alpha + gamma -, and gamma -phase fields were represented. Creep, tensile, and hardness measurements were obtained between 80 and 1700 deg F. The plasticity reserve'' of Ivanova (rupture time times minimum creep rate) and the empirical relation of Monkman and Grant (between rupture time and minimum creep rate) are examined from a common viewpoint. Both compositional and temperature dependences are established in their relationships. The combined stress-time function is applied to isochronous stress-strain curves out to strains of 30%. Curves of plasticity reserve, ductility at fracture, break (equicohesive) temperature, and the constants in the Rabotnov and Larson-Miller parameters are shown to be related. The strength and stability of the alloys are examined with reference to their break temperatures. The strength of single- phase alloys varies with break temperature, but two-phase alloys show no simple dependence. The hardening influence'' of titanium, beryllium, manganese, cobalt, and nickel solutes reveals both solution hardening and solution softening at elevated temperatures. An opposite strain-rate effect is apparent on the ductilily at fracture of alpha and gamma alloys. The strength-hardness correlation proposed earlier has been verified withmore » Alloy S-590 over wide ranges of stresses, times, and temperatures. An inversion in the relative strengthening ability of alloys with coarse and fine spacings appears to conform to the scheme advanced by Giedt. Sherby, and Dorn. (auth)« less

Authors:
; ; ;
Publication Date:
Research Org.:
Battelle Memorial Inst., Columbus, Ohio
OSTI Identifier:
4295406
Report Number(s):
WADC-TR-56-184(Pt.3); AD-15565
NSA Number:
NSA-13-000765
DOE Contract Number:
AF33(616)-2785
Resource Type:
Technical Report
Resource Relation:
Other Information: Project title: SOLID STATE RESEARCH AND PROPERTIES OF MATTER. Task title: INTERACTIONS, IMPERFECTIONS, AND ALLOY THEORY. Orig. Receipt Date: 31-DEC-59
Country of Publication:
United States
Language:
English
Subject:
METALLURGY AND CERAMICS; BERYLLIUM ALLOYS; CHROMIUM ALLOYS; COBALT ALLOYS; DEFECTS; DUCTILITY; HIGH TEMPERATURE; IRON ALLOYS; MANGANESE ALLOYS; MECHANICAL PROPERTIES; NICKEL ALLOYS; PHASE DIAGRAMS; SOLID SOLUTIONS; TENSILE PROPERTIES; TITANIUM ALLOYS

Citation Formats

Underwood, E.E., Wolff, A.K., Marsh, L.L., and Manning, G.K.. THE PRINCIPLES OF DISPERSION HARDENING WHICH PROMOTE HIGH-TEMPERATURE STRENGTH IN IRON-BASE ALLOYS. Period Covered: March 1, 1957 to February 29, 1958. United States: N. p., 1958. Web.
Underwood, E.E., Wolff, A.K., Marsh, L.L., & Manning, G.K.. THE PRINCIPLES OF DISPERSION HARDENING WHICH PROMOTE HIGH-TEMPERATURE STRENGTH IN IRON-BASE ALLOYS. Period Covered: March 1, 1957 to February 29, 1958. United States.
Underwood, E.E., Wolff, A.K., Marsh, L.L., and Manning, G.K.. Tue . "THE PRINCIPLES OF DISPERSION HARDENING WHICH PROMOTE HIGH-TEMPERATURE STRENGTH IN IRON-BASE ALLOYS. Period Covered: March 1, 1957 to February 29, 1958". United States. doi:.
@article{osti_4295406,
title = {THE PRINCIPLES OF DISPERSION HARDENING WHICH PROMOTE HIGH-TEMPERATURE STRENGTH IN IRON-BASE ALLOYS. Period Covered: March 1, 1957 to February 29, 1958},
author = {Underwood, E.E. and Wolff, A.K. and Marsh, L.L. and Manning, G.K.},
abstractNote = {Eleven alloys, based on iron--18% chromium, were prepared with up to 16% nickel so that the alpha -, alpha + gamma -, and gamma -phase fields were represented. Creep, tensile, and hardness measurements were obtained between 80 and 1700 deg F. The plasticity reserve'' of Ivanova (rupture time times minimum creep rate) and the empirical relation of Monkman and Grant (between rupture time and minimum creep rate) are examined from a common viewpoint. Both compositional and temperature dependences are established in their relationships. The combined stress-time function is applied to isochronous stress-strain curves out to strains of 30%. Curves of plasticity reserve, ductility at fracture, break (equicohesive) temperature, and the constants in the Rabotnov and Larson-Miller parameters are shown to be related. The strength and stability of the alloys are examined with reference to their break temperatures. The strength of single- phase alloys varies with break temperature, but two-phase alloys show no simple dependence. The hardening influence'' of titanium, beryllium, manganese, cobalt, and nickel solutes reveals both solution hardening and solution softening at elevated temperatures. An opposite strain-rate effect is apparent on the ductilily at fracture of alpha and gamma alloys. The strength-hardness correlation proposed earlier has been verified with Alloy S-590 over wide ranges of stresses, times, and temperatures. An inversion in the relative strengthening ability of alloys with coarse and fine spacings appears to conform to the scheme advanced by Giedt. Sherby, and Dorn. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Apr 01 00:00:00 EST 1958},
month = {Tue Apr 01 00:00:00 EST 1958}
}

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  • The strength properties of an Fe--20% Cr-base alloy, as influenced by ternary additions of Be, Ti, V, Mn, Co, or Ni, were studied from 80 to 15OO deg F. Property changes in these single and polyphase alloys were followed by means of creep, tensile, and hardness tests, augmented by metallographic and x-ray measurements. Although roomtemperature tensile strengths increased initially with solute concentration, creep-rupture tests at 12OO deg F revealed solid- solution sofiening. Alloys with the greatest room-temperature lattice distortion exhibited the greatest decrease in rupture stress. A periodicity was found in the strengthening influence of ternary solutes, whereby the furthermore » the solute element stood from Fe (in the fourth period of the periodic table), the greater the strength in- crease. A qualitative correspondence was established be tween the slopes of time-dependent hot-hardness curves and the slopes of stress-rupture time curves. These "stability'' curves are simllar to those of "break'' temperatures for the sanne alloys. The strength-hardness correlation, proposed earlier, has received considerable experimental confirmation. A linear relation is suggested between the strengthening due to particles at 12OO deg F and their spacing, and for the particular alloy and conditions studied, the strengthening increment increases with increasing particle spacing. (auth)« less
  • Studies were conducted to determine the importance of beta grain size as a contributing factor to the loss of ductility that occurs when titanium alloys are heat treated at temperatures above thc beta transus. in a second phase of the research a heat-treatment program was carried out in an effort to develop procedures for restoring ductility in beta-embrittled material. To supplement these studies, a microscopic study of deformation in pcrtincnt microstructores was conducted. The primary cause of beta embrittlemcnt is the large grain size which is obtained so rapidly in many alpha-beta titanium alloys when heated into thc beta field.more » Grainboundary alpha and acicular intragranular alpha in the microstructure are not detrimental if the beta grain size is fine. The structures resulting from beta treatments anre quite stable and can not bc significantiy altered in a beneficial way by heat treatment alone. Certain alloys (such as Ti-16V-2.5Al) show a relatively low rate of beta grain growth. Development of alloys exhibiting this property appears to offer the most promising means of avoiding or minimizing beta-embrittiemeat effects. (auth)« less
  • The notch tensile propenties of three commercial titanium-base alloys, A110AT (Ti -5.0Al--2.5Sn), Ti6Al-4V, and Ti-140A (Ti-2Fe-2Cr-2Mo), were investigated at six interstitial levels, four microstructural conditions, and over a range of temperatures from - 196 to 200 C. Notch sensitivity generally was increased by increased interstitial content, low temperature, and acicular- type microstructures. In addition, sensitivity to slow-strain hydrogen embrittlement was observed in the temperature range near 0 C at hydrogen levels well below specification limits. (auth)
  • A fill and drain sealant based on Viton A was developed which has excellent resistance to fuels at 450 F. The fill and drain system consists of a dilute solution of Viton A and phenolic resins is a primer, a Viton A sealant compounded with silicone coated silica and magnesium oxide at 28% solids in methyl isobutyl ketone and an amine curing solution. An 80% solids filleting sealant with excellent resistance to fuel and dry heat at 450 F and adequate low temperature properties has been developed from Viton A cured with hexamethylene diamine. The sealant can be cured adequatelymore » in one hour at 250 F but requires an additional 2 hours at 350 F to develop adhesion. A 100% solids filleting formulation based on PAH-1 was cured with benzoyl peroxide to an elastomeric material which had excellent resistance to Type IfI and JP-5 fuels at 350 F, but its initial tensile strength properties were not of a very high order. A groove sealant formulated from LS53U and 1F4 maintained its seal and was capable of reinjection after 6 days immersion in Type II reference fluid or jP-4 fiuid at 275 F followed by 7 days at 350 F or 2 days at 450 F with equally satisfactory results. The compound met the major requirements of the proposed 250 F Military Groove Sealant Specification and the sealing and reinjection requirements of this specification when tested at 350 and 450 F. Compounds were developed which should be suitable for use as non-fuel resistant pressurization sealants for high-temperature. exposures to 700 F. Formulations are based on roomtemperature vulcanizing silicone compounds. For elevated temperature service a stepwise post cure up to the anticipated operating temperature is required. (auth)« less
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