CN1061279C

CN1061279C - Method for producing Fe-Al or Fe-3Al metal meta-compound elements

Info

Publication number: CN1061279C
Application number: CN96118708A
Authority: CN
Inventors: 李琎
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-06-21
Filing date: 1996-06-21
Publication date: 2001-01-31
Anticipated expiration: 2016-06-21
Also published as: CN1169346A

Abstract

The present invention relates to a method for manufacturing a Fe-Al or Fe-3Al metal-compound element by powder metallurgy, which comprises: firstly, melting pure ferrum and pure aluminium to obtain a compound powder of Fe2Al5, FeAl2 or FeAl3; proportionally adding a pure ferrous powder, and mixing the pure ferrous powder with the compound powder; then pressing and forming the powders at a normal temperature, and adopting liquid phase to sinter to obtain a required element. The present invention has the advantages of simple process, low manufacturing cost, and high density and uniform ingredient of elements.

Description

Make the method for iron aluminium or Fe-3 Al metal meta-compound elements

The invention belongs to field of powder metallurgy, is a kind of method of making iron aluminium or Fe3Al intermetallic compound part.

Iron aluminium (FeAl) in iron-Al series metal compounds and iron three aluminium (Fe3Al) compound have many good performances, as light specific gravity, higher intensity and enough toughness, good oxidation-resistance and corrosion stability etc.But owing to be subjected to the restriction of existing manufacturing process, so far and fail to be widely used.

The method of making FeAl or Fe3Al intermetallic compound part at present mainly contains following three kinds:

1, with an amount of iron and aluminium fusing, be cast into FeAl or Fe3Al ingot casting, the method by mechanical workout is processed into required part again.This method is owing to must adopt a series of special thermal processing methods to eliminate casting flaw, and follow-up machining amount is big, difficulty is higher, so the technology of this method is complicated, cost is very high.

2, at first melt an amount of iron and aluminium, make FeAl or Fe3Al powder, adopt powder metallurgy method to pass through compacting, sintering acquisition FeAl or Fe3Al embryo spare again.This method is owing to be solid state sintering, and the density of sintered part is lower, so also must improve its density by heat pressing process.Obviously, adopt pressure sintering to make technology become complicated, and manufacturing cost is also higher.

3, the method for stretching certainly: be pressed into embryo spare after an amount of iron powder and aluminium powder mixed, be heated to certain temperature then, make between these two kinds of pure metal powders to react, directly generate required FeAl or Fe3Al intermetallic compound part.Reaction between iron, aluminium is thermopositive reaction, and its speed of response is very fast again, so the temperature variation in the reaction process is very fast, makes the emitting of restive powder surface adsorbed gas in the actually operating, the expansion between different tissues, shrink also inhomogeneous.Still there are many cavities in the material of reaction back gained, and the distortion of embryo spare is also bigger.Eliminate its defective so also must adopt hot-press method.

The purpose of this invention is to provide a kind of technology is simple, manufacturing cost the is lower manufacturing FeAl or the method for Fe3Al intermetallic compound part.

The objective of the invention is to realize by following approach: the manufacturing iron aluminium that is provided or the method for Fe-3 Al metal meta-compound elements are:

1〉produces Fe2Al5 or FeAl3 or FeAl2 metal compound powders;

2〉press the atomic ratio of required iron aluminium or Fe-3 Al metal meta-compound with straight iron powder and preceding fast Fe2Al5 or FeAl2 or FeAl3 metal compound powders and an amount of surface protection, mix lubricant;

3〉under the normal temperature above-mentioned mixed powder is pressed into the pressure embryo of required part,

4〉above-mentioned pressure embryo is carried out liquid phase sintering, promptly obtain required intermetallic compound part.

The present invention adopts indirect mode to make FeAl or Fe3Al intermetallic compound part according to the characteristics of iron-Al series metal compounds, promptly select for use Fe2Al5 or FeAl3 or FeAl2 metallic compound as intermediate compound earlier, again it is mixed with straight iron powder, compacting, sintering.Compare with the existing method of directly obtaining FeAl or Fe3Al part with iron, aluminium, simple, the low cost of manufacture of technology not only, but also following advantage is arranged: 1. the prices of raw and semifnished materials are cheap.Fe2Al5, FeAl3 or FeAl2 metallic compound are highly brittle, so can adopt traditional mechanical means that its ingot casting is crushed to fine powder, also can adopt traditional atomization to obtain their fine powder certainly.2. the present invention utilizes the fusing point of Fe2Al5, FeAl3 or FeAl2 metallic compound low than pure iron, and their atomic ratio has the characteristics of certain gap again with the atomic ratio of FeAl and Fe3Al, adopted liquid phase sintering, (under sintering temperature, Fe2Al, FeAl2 or FeAl3 are molten into liquid phase in short-term).Therefore, the part density that is obtained is very high, and composition is even.3. most of reaction heat is emitted when obtaining Fe2Al5, FeAl3 or FeAl2 compound powder with iron, aluminium, is significantly reduced by reaction heat in the process of Fe2Al5, FeAl3 or FeAl2 and pure iron reaction generation FeAl or Fe3Al.Therefore, sintering process of the present invention is more steady, easily control (as heat-up rate, liquid phase quantity etc.), not only guaranteed required density, and can guarantee to press embryo in sintering process, to shrink evenly, thus can directly obtain more accurate part shape, significantly reduced follow-up amount of machining.

In sum, technology of the present invention is simple, manufacturing cost is lower, and can obtain high-quality part, for new approach has been opened up in the widespread use of FeAl and Fe3Al intermetallic compound.In addition, indirect method provided by the present invention also can be applicable to the manufacturing of some other intermetallic compound part.As: nickel-aluminium system, can select for use the Ni2AL3 powder to mix and make Ni3AL or NiAL part with the Ni powder; Molybdenum-silicon system, iron-silicon system also can adopt similar method.

Example one

Make the cylindrical component of FeAl3 intermetallic compound, its diameter and highly be 30mm, the atomic percent that requires aluminium is 28% (atomic percent of Fe3Al can change within the specific limits).

1〉will make the Fe2Al5 ingot casting, (also can add alloying elements such as a spot of Mo, Cr, B when melting as required) after iron, the aluminium fusing;

2〉broken Fe2Al5 ingot casting, and carry out ball milling, obtain the Fe2Al5 fine powder of granularity less than 15 μ m;

3〉with straight iron powder and above-mentioned Fe2Al5 powder and an amount of surface protection, mix lubricant, wherein the weight ratio of straight iron powder and Fe2Al5 powder is 71: 29; Surface protection, lubricant select paraffin, and its amount is about 0.6% of gross weight.

4〉at normal temperatures above-mentioned mixed powder is pressed into the pressure embryo, pressing force is 100-200MPa;

5〉will press embryo sintering under protective atmosphere, sintering temperature is 1300-1380 ℃, and the time is 20 minutes, promptly gets required Fe3Al compound elements behind the sintering.

Example two

Make FeAl intermetallic compound cylindrical component, the atomic percent that requires aluminium is 40%.

1〉produces the Fe2Al5 powder by example one;

2〉straight iron powder is mixed with Fe2Al5 powder and an amount of paraffin, the weight ratio of iron powder and Fe2Al5 powder is 55: 45;

3〉mixed powder is pressed into embryo under 100-200MPa pressure, and under protective atmosphere sintering, promptly get required part.Sintering temperature is 1200-1290 ℃, and the time is 20 minutes.

The present invention the most handy Fe2Al5 or FeAl3 compound powder when making FeAl intermetallic compound part mix with iron powder, so that make the iron powder of adding occupy enough ratios.

Basic identical with technological process and above-mentioned example that FeAl2 or FeAl3 make Fe3Al or FeAl intermetallic compound as intermediate compound of the present invention.

Claims

1, make the method for iron aluminium or Fe-3 Al metal meta-compound elements, it is characterized in that:

1〉produces Fe2Al5 or FeAl3 or FeAl2 metal compound powders;

2〉press the atomic ratio of required iron aluminium or Fe-3 Al metal meta-compound with straight iron powder and aforementioned Fe2Al5 or FeAl2 or FeAl3 metal compound powders and an amount of surface protection, mix lubricant;

2, the method for claim 1 is characterized in that mixing with straight iron powder with Fe2AL5 or FeAl3 compound powder when making the intermetallic Fe-Al compound part.