DEVELOPMENT OF PARTIALLY VOLATILE BRAZING FILLER ALLOYS FOR HIGH- TEMPERATURE APPLICATION AND RESISTANCE TO OXIDATION. Final Report covering period April 1, 1958 to March 31, 1959
Experimental brazing filler alloys have been developed containing temperature depressants which have been volatilized during the brazing of stainless steel leaving joints of high remelt temperature. The mechanisms by which remelt temperature is increased have been studied for the range of alloys investigated which contained nickel, chromium, germanium, iron, lithium, and phosphorus. The two main mechanisms are (1) dissolution of the base metal in the filler metal and diffusion of constituents of the filler metal into the base metal and (2) volatilization of the filler metul constituents. It has been shown theoretically and experimentally that in order for remelt temperature to increase there must be solid solubility of the diffusing or volatile element in the filler alloy. Although compositional changes may result from either mechanism, a remelt temperature change does not necessarily occur. The degree to which a compositional change affects remelt temperature is proportional to the solid solubility. In this program, vacuum pumping was the more efficient vapor-removal method among several discussed and investigated. Furthermore, under vacuum the surfacearea-to-volume ratio of the filler alloy becomes less rate-controlling due to boiling. Boiling, however, causes porosity in the joint. i0f the alloys investigated a 61% Ni--39% ln alloy exhibited the greatest remelt temperature rise due to volatilization alone, whereas a 94% Ni--6% P responded only to dissolution and diffusion to exhibit the largest rise in remelt temperature due to this mechanism. Ni--Cr--In--Ge alloys exhibited a substantial rise in remelt temperature due 10 the operation of both mechanisms. This alloy and the binary Ni--In alloy can be considered practical alloys for hightemperature usage. A direct effect of metallic vapors on wetting and flow of the filler alloy was observed and subsequently discussed with respect to their influence on surface tension relationships. It has been shown that in the presence of metal vapors, discoloration of the base metal, wetting, flow, and skull formation of the filler alloy are functions of the rate and quantity of metal vapor removal. (auth)
- Research Organization:
- Illinois Inst. of Tech., Chicago. Armour Research Foundation
- DOE Contract Number:
- AF33(616)-5654
- NSA Number:
- NSA-13-020190
- OSTI ID:
- 4226725
- Report Number(s):
- WADC-TR-59-404
- Resource Relation:
- Other Information: Project title: METALLIC MATERIALS. Task title: WELDING AND BRAZING OF METALS. Orig. Receipt Date: 31-DEC-59
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BOILING
BRAZING
CEMENTS
CHROMIUM ALLOYS
COLOR
CONTROL
DIFFUSION
GERMANIUM ALLOYS
HIGH TEMPERATURE
IMPREGNATION
INDIUM ALLOYS
IRON ALLOYS
JOINTS
LITHIUM ALLOYS
NICKEL ALLOYS
NICKEL COMPOUNDS
OXIDATION
PHOSPHORUS COMPOUNDS
POROSITY
PUMPS
SOLID SOLUTIONS
SOLUTIONS
STABILITY
STAINLESS STEELS
SURFACE TENSION
SURFACES
USES
VACUUM
VAPORS
VOLATILITY
VOLUME
WELDING