The Application of High Pressure in Metal-deformation Processing
The Application of High Pressure in Metal-deformation Processing

Author: F. W. Boulger

Publisher:

Published: 1964

Total Pages: 82

ISBN-13:

DOWNLOAD EBOOK

On October 3, 1963, a symposium was sponsored by the Bureau of Naval Weapons, Metalworking Processes and Equipment Program, on the application of high pressure in metal-deformation processing. Past research has shown that superimposed hydrostatic pressure can significantly increase the ductility at fracture of various materials. These observations have stimulated considerable interest in applying this hydrostatic-pressure effect to metal deformation processing, where it was anticipated that improved ductility and fabricability of brittle materials could be realized. Hydrostatic extrusion and hydrodynamic compressive forging were two such fabrication techniques discussed at the symposium, and preliminary results were found to be encouraging. Another fabrication process that will be investigated in the near future is sheet drawing, where the effect of superimposed pressure improves the ductility to fracture, it was noted that pressure cycling did not improve either the strength or ductility of steels containing various amounts of carbon. In addition to the mechanical-property effects, hydrostatic pressure has been found to affect measurably, numerous metallurgical properties of metals and alloys. (Author).

Oxidation of Nickel- and Cobalt-base Superalloys
Oxidation of Nickel- and Cobalt-base Superalloys

Author: Carl H. Lund

Publisher:

Published: 1965

Total Pages: 38

ISBN-13:

DOWNLOAD EBOOK

This report presents information dealing with the oxidation of nickel- and cobalt-base superalloys. All of the superalloys will oxidize at high temperatures when oxygen is present in the enveloping atmosphere. The rate of oxidation depends upon alloy composition, temperature, oxygen concentration, oxides formed, diffusion rates of the metals in both base metal and oxide, diffusion rate of oxygen in the oxide, solubility of oxygen in the matrix, and a host of other variables. The effects of oxidation can be beneficial or they can be harmful. The first section of this report deals with the fundamentals of the oxidation of Ni-Cr and Co-Cr alloys. Subsequent sections discuss general surface oxidation, intergranular oxidation, other subsurface oxidation, and the effect of stress on the rate of oxidation. Numerous specific alloys are mentioned in the report; as an aid to the reader, the appendix contains an alloy index of the alloys mentioned in the report along with the compositions of the alloys, and the pages on which mention of the alloys is made.

Premium-quality Aluminum Castings
Premium-quality Aluminum Castings

Author: K. R. Grube

Publisher:

Published: 1965

Total Pages: 52

ISBN-13:

DOWNLOAD EBOOK

Premium-quality castings are those which are guaranteed to show a specified high level of mechanical properties. The properties currently being achieved represent significant improvements over those which can be achieved in conventional aluminum-alloy castings and approach the properties currently obtainable in wrought aluminum alloys. These property advances are largely the result of improved casting technique and design. These castings are gradually finding acceptance and usage in aerospace applications, thanks to integrated efforts between the casting producers and their customers. (Author).

The Effects of High Pressure, High Temperature Hydrogen on Steel
The Effects of High Pressure, High Temperature Hydrogen on Steel

Author: Ellis E. Fletcher

Publisher:

Published: 1964

Total Pages: 82

ISBN-13:

DOWNLOAD EBOOK

This report deals with the deleterious effects of hydrogen gas on steel at elevated temperatures and/or pressures. Hydrogen attack on steels is manifest as decarburization, intergranular fissuring, or blistering. These conditions result in lowered tensile strength, ductility, and impact strength. The reaction of hydrogen with iron carbide to form methane is probably the most important chemical reaction involved in the attack on steel by hydrogen. Attack of steel at elevated temperatures and pressures is limited or prevented by the following measures: (1) use of steel alloyed with strong carbide-forming elements, (2) use of liners of resistant alloy steels, and (3) substitution of resistant nonferrous alloys.

Current Methods of Fracture-toughness Testing of High-strength Alloys with Emphasis on Plane Strain
Current Methods of Fracture-toughness Testing of High-strength Alloys with Emphasis on Plane Strain

Author: J. E. Campbell

Publisher:

Published: 1964

Total Pages: 32

ISBN-13:

DOWNLOAD EBOOK

Fracture-toughness testing using principles of fracture mechanics has developed to the point where it can be used as a basis for selection of materials, for estimating limiting design stresses assuming the presence of small flaws, and for analyzing failures. Current methods of measuring plane-stress and plane-strain fracturetoughness parameters are presented in this report. The specimens include center-cracked, edge-cracked, single-edge-cracked, surface-cracked, and notched round bars, which are subjected to tensile loading, and notched bars for bend tests. The different types of specimens permit evaluating sheet, plate, bar stock, and forgings as well as material from failed structures. Application of fracture-toughness parameters to design of high-strength structures is reviewed for both static and fatigue loading. Consideration of the fracture-mechanics concepts in design should lead to fewer problems with brittle fracture in high-strength structures. (Author).