Aluminum dispersion-strengthened

The technique of rapid soHdification enables relatively large amounts of insoluble metallic elements to be finely dispersed within atomized powders. Upon freezing very small intermetaUic particles are formed, resulting, after further processing, in a high volume fraction of finely dispersed particles within the aluminum matrix and hence a dispersion strengthened aUoy. The intermetaUic phases, or possibly oxidic species, responsible for the dispersion strengthening are probably binary Al-Fe and ternary Al—Fe—Ce compounds. 

Extremely high softening resistance is available in alloy C15720 through dispersion strengthening by aluminum oxide. This alloy has been used successhiUy as a welding rod material and in other specific appHcations that can bear its cost. 

Figure 5.81 Strength of dispersion-strengthened aluminnm compared with wronght aluminum. Reprinted, by permission, from M. Schwartz, Composite Materials Handbook, 2nd ed., p. 1.29. Copyright 1992 McGraw-Hill Book Co.

Figure 5.82 The strength of different dispersion-strengthened alloys relative to the pure metal strength as a function of relative temperature. Preparation techniques include sintered aluminum powder (SAP), internal oxidation, and salt decomposition. Reprinted, by permission, from A. Kelly, Composite Materials, p. 62. Copyright 1966 by American Elsevier, Inc.

Abstract Dispersion strengthened aluminum compacts have been prepared by powder... 

Key words Dispersion strengthened materials, aluminum, microstructure, mechanical properties... 

A mode of mechanical alloying is reaction milling, developed for dispersion strengthened aluminum production [1], To produce aluminum dispersoid the aluminum powder is intensively dry milled with carbon powder. The transformed dispersed phase A14C3 is than produced by a chemical reaction, which starts during milling, and it is completed at the next heat treatment process. The resulting powder mixture is then pressed,... 

The aim of this paper is to study the influence of the various graphite types when mixed with A1 powder, and heat treatment procedure on the microstructure and properties of dispersion strengthened aluminum type Al-AI4C3. The influence of carbides characteristics on mechanical properties is evaluated together with the influence of applied deformation mode on the microstructure development and mechanical properties. 

Anode Unalloyed porous nickel anodes used by early developers were found to shrink during operation under the stack compressive load, resulting in undesired dimensional change, reduced surface area, and lower electrochemical performance. Alloying with chromium and/or aluminum provides oxide dispersion strengthening, resulting in adequate creep strength. Excellent mechanical and chemical stability of the baseline Ni-Al anode is verified in an 18,000 h field operation. Fig. 8 shows that the structure of the... 

Microstmcture of Rodent after casting is composed of large grains/den-drites of the austenite matrix, which is the solid solution of nickel strengthened chromium and molybdenum. The matrix is additionally strengthened by dispersion of molybdenum silicide precipitates. A small number of carbide and aluminum oxide particles were also observed. The presence of eutectics y-P rather weakens the structure of the alloy. 

---