Method for preparing oxide dispersion strengthened iron-base alloy

Abstract

The invention discloses a method for preparing an oxide dispersion strengthened iron-base alloy, and belongs to the technical field of metal dispersion strengthening. The method comprises the following steps of: taking iron blocks, a Fe-Mn alloy and an Ni-Al alloy as raw materials, performing a vacuum smelting and electroslag smelting duplex process to obtain a pure intermediate alloy cast ingot; crushing the intermediate alloy cast ingot in a crusher with protective atmosphere to obtain intermediate alloy powder; and performing high-energy ball-milling on intermediate alloy powder, matrix powder and oxide powder to obtain the oxide dispersion strengthened iron-base alloy. Oxide dispersion strengthened iron-base alloy powder is subjected to hot isostatic pressing treatment and thermal treatment to obtain the final oxide dispersion strengthened iron-base alloy. The method adopts the duplex smelting process, so that content of oxygen and nonmetal impurities in cast ingot is effectively reduced; the alloyed intermediate alloy prevents oxidization of an element Mn, ball-milling time can be shortened and energy consumption is reduced. The prepared oxide dispersion strengthened iron-base alloy is co-strengthened by a L21 type Ni2AlMn intermetallic compound and an oxide dispersed phase, so that the strengthening effect is remarkable.

Description

technical field [0001] The invention belongs to the technical field of metal dispersion strengthening, and particularly provides a method of preparing master alloy powder by master alloy method, and then mechanically alloying master alloy powder, matrix powder and oxide powder to obtain oxide dispersion strengthening iron-based alloy powder. method. Background technique [0002] Ferritic alloys strengthened by intermetallic compounds and nano-oxides have a γ / γ' two-phase structure similar to nickel-based alloys, which is expected to improve the service temperature limit and high-temperature mechanical properties of traditional ferritic heat-resistant alloys. There are important application prospects in the field of high temperature structural materials. Nano-oxide particles have excellent thermal and chemical stability. At a temperature close to the melting point of the alloy, nano-oxides can still hinder the movement of dislocations. It is the most important strengthening ...

AI Technical Summary

Problems solved by technology

[0003] In the preparation of L2 by conventional mechanical alloying process 1 Type Ni 2 When the oxide dispersion strengthened iron-based alloy strengthened by AlMn intermetallic compounds and oxides, Ti and Mn elements are easy to be oxidized during the mechanical alloying process, not only to participate in the formation of Ni 2 The Mn element of AlMn intermetallic compound is reduced, and the purpose of effectively controlling the composition of intermetallic compound cannot be achieved

Inclusions easily introduced by long-time ball milling and non-metallic inclusions (Al-Mg-O) in raw materials will reduce the high-temperature mechanical properties of materials

At the same time, the oxidation of Ti and Mn elements increases the content of impurity oxygen, resulting in the coarsening of the oxide dispersed phase.

The above two factors are directly related to the structure and thermal stability of intermetallic compounds and oxides, which limit the improvement of strengthening effect

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