A kind of preparation method of high-strength oxide dispersion strengthened Fe-based alloy

Abstract

The invention provides a method for preparing a high-strength oxide dispersion-strengthened Fe-based alloy. A new oxidation treatment process is adopted to utilize the easy segregation of active elements in dislocations, vacancies and grain boundaries and the ease of oxygen elements along dislocations and vacancies. and the inward diffusion characteristics of grain boundaries to realize the effective combination of oxygen and active elements and the control of oxygen content; and then use the Ar / H 2 The protection of the mixed gas and the brittleness of the oxidized particles make the oxidized alloy powder broken and cold-welded within a few hours, increasing the internal dislocations and vacancies of the powder without changing the oxygen content, reducing the grain size, and enhancing the diffusion ability of alloying elements , the thermally cured ODS alloy has higher dislocation density, finer grain size and dispersed composite nano-oxide particles, so as to obtain high-strength mechanical properties and creep properties. The prepared ODS-Fe-based The method of alloying is low in cost and high in production efficiency.

Description

technical field [0001] The invention relates to the preparation technology of oxide dispersion strengthened alloys, and specifically provides a novel preparation method which saves time and cost, can be mass-produced, and realizes high-strength oxide dispersion strengthened FeCrAl or FeCr alloys. Background technique [0002] Oxide dispersion strengthened (Oxide dispersion strength, ODS) Fe-based alloy has become one of the few metal materials that can be used in environments above 1000 °C due to its excellent creep resistance, oxidation resistance and high strength properties. Its excellent macroscopic properties are mainly derived from the nano-oxide particles Y-Al-O or Y-Ti-O dispersed in the matrix. When the material is plastically deformed, the nano-oxide particles interact with dislocations and grain boundaries. Dislocations and grain boundaries play a pinning role. If dislocations and grain boundaries want to overcome obstacles and continue to move, they need to rely ...

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Problems solved by technology

But at the same time, the mechanical alloying method also has shortcomings: the ball milling time required for alloying is long, ranging from tens of hours to hundreds of hours, resulting in high time and cost of ODS alloy preparation and low production efficiency; The pollution of the alloy powder by the process control agent is unavoidable, resulting in differences in the properties of batches of alloys; the oxygen content of mechanical alloying cannot be controlled, and the different protective gases for ball milling lead to different oxygen content of the alloy powder after ball milling, so it is necessary to carry out Fe-based ODS Research on New Preparation Method of Alloy

The chemical infiltration method and co-precipitation method are completed in the laboratory, and the dispersed phase obtained in the experiment is not Y-Al-O or Y-Ti-O nano-oxide particles, but Y 2 o 3 Particles, large particle size, resulting in low alloy strength

The traditional internal oxidation method is to directly heat the alloy powder containing active elements to a high temperature in an oxygen-containing atmosphere, or then reduce it with hydrogen. It is assumed that oxygen only reacts with active elements and not with inert metal elements. In fact, this process is very difficult. control

Anderson in the Iowa laboratory of the United States oxygenated FeCr alloy powder by spraying oxygen (patent number: US 8,864,870 B1), and obtained Y-Ti-O and Y-Hf-O dispersion-strengthened ODS alloys after hot isostatic pressing , this preparation method has high requirements for atomization powder making equipment, and the oxygen content of the powder obtained by atomization cannot be controlled. The most important point is that the patent specifically indicates that this method is not suitable for the preparation of ODS iron-based alloys containing Al. The reason is that under extremely high temperature spray conditions (1500-1800°C), even a small amount of oxygen will quickly combine Al and oxygen in the Fe-based alloy powder, thereby forming dense Al on the surface of the powder. 2 o 3 membrane, thereby preventing the inward diffusion of oxygen

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