JPH0436408A - Manufacture of high strength structural member - Google Patents

Abstract

PURPOSE:To manufacture a high strength structural member by degassing alloy powder composed of amorphous single phase alloy powder, etc., and dispersed with oxygen gas on the outer peripheral part with heating treatment and executing pressurize forming treatment. CONSTITUTION:Raw material powder 1a composed of amorphous single phase alloy powder, etc., having <about 22 mu average particle diameter and with the oxygen gas diffused on the outer peripheral part 2, is charged into a die 11 in a vacuum chamber 10 of hot press apparatus 9 to make an assembly 1. Inner part in the vacuum chamber 10 is held to the prescribed vacuum degree and the assembly 1 is heated at the crystallize temp. or more with a heater 12 and the degassing treatment is executed to the assembly 1. Successively, the pressurizing force is applied to the assembly 1 with a punch 13 to execute the pressurize forming treatment and the sintering is executed. By this method, the powders are mutually and sufficiently joined and a high strength structural material is manufactured.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a method for manufacturing a high-strength structural member, and in particular, a method for obtaining the member by sintering (including compacting and solidifying) raw material powder. Regarding improvements.

(2) Conventional technology Conventionally, various raw material powders have been used in the above manufacturing method, but when aiming to further increase the strength of structural members, for example, amorphous single-phase alloy powder is used as the raw material powder. It is possible to use it.

The reason for this is that when the alloy powder is subjected to a thermal history higher than the crystallization temperature Tx, a fine crystal structure appears uniformly even though it is a high alloy. This is because we can expect

(3) Problems to be solved by the invention However, when the above-mentioned alloy powder is used as a raw material powder, it is difficult to sufficiently bond the powders together during sintering, and as a result, it is difficult to obtain a member with the expected strength. The problem is that it cannot be done.

In view of the above, an object of the present invention is to provide the above-mentioned manufacturing method that can firmly bond powders together to obtain a structural member with high strength and high toughness.

B0 Structure of the Invention (1) Means for Solving the Problems The present invention provides for producing a high-strength structural member by sintering a raw material powder, using an amorphous single-phase alloy powder as the raw material powder;
At least one type selected from a mixed phase alloy powder containing an amorphous phase and a crystalline phase, and a supersaturated solid solution powder having a composition similar to the amorphous phase forming composition, in which oxygen gas is diffused in the outer periphery. In the sintering step, the oxygen gas is discharged from the aggregate of the raw material powder, and the aggregate is subjected to a pressure forming process.

(2) Effect In the oxygen gas discharge process, the oxygen gas present in the outer periphery of the raw material powder is
While crushing the oxide film, the powder is discharged while moving from one powder to the other, thereby activating the outer surface of the raw material powder. When an aggregate of raw powder is subjected to pressure molding under these circumstances, the outer surfaces of the activated powders come into close contact with each other, creating a neck (contact) between them, which causes The raw material powders can be sufficiently bonded to each other.

(3) The amorphous single-phase alloy powder, the mixed alloy powder containing an amorphous phase and a crystalline phase, and the supersaturated solid solution powder having a composition similar to the amorphous forming composition used as the raw material powder in the examples are as follows: Manufactured by a liquid quenching method such as high-pressure helium gas atomization method. As shown in FIG. 1, the raw material powder 1a has a layer on its outer periphery 2 in which oxygen gas is diffused, and the outer surface may be covered with an oxide film 3.

The amorphous single phase alloy powder includes AiA, Ni, Y
,,,All@aN f IoCeh, Aj! ma
N j +oD Vh , A1m5N is Y@CO
x, AfssF et, s Yq, s, AfeoN
i IoCa to, M g *zN i s Y
This corresponds to an alloy powder having a composition such as to, MgtiNi+oCe1oCr4 (values are atomic %).

Further, as the mixed alloy powder, An! *zFesY3
,Aj! s3N is Y+. Bz, Aj2s3N
i5 Y+.

Nbz, A1. ssN 14 Cab, A1. oN
It Y3, AfHF e6 Y3, Mg5sN
This includes alloy powders having compositions such as is Ceq and MgmbN ih Ys (values are in atomic %).

Further, as the supersaturated solid solution powder, AlqzN 1
s Ys, A f? . N 16Dy4 , Alq
xN 14Dya, Aj2qoN is Cas,
AlqaFex Y3, Mg5sN is Y7, M
An alloy powder having a composition such as g5sN ih Ceh (values are atomic %) falls under this category.

In addition, even if the composition is the same as the amorphous single-phase alloy powder, due to the difference in cooling rate during production, those with a small average diameter will become amorphous single-phase alloy powder, and those with a large average diameter will become amorphous single-phase alloy powder. is a crystalline single-phase alloy powder, and when the average diameter is between these, it is a mixed-phase alloy powder of an amorphous phase and a crystalline phase.

As an example, A j2 ssN I s Ys CO
A molten metal having a composition of 2 (values are atomic %) was prepared, and the molten metal was used to produce alloy powder by applying a high-pressure helium gas atomization method.

In this alloy powder, the powder having an average diameter of less than 22 μm consists entirely of an amorphous phase, and is therefore an amorphous single-phase alloy powder. The crystallization temperature Tx of this amorphous single-phase alloy powder is 299.5°C.

Further, powder having an average diameter of 22 μm or more and 44 μm or less consists of an amorphous phase and a crystalline phase, and is therefore a mixed phase alloy powder. Moreover, powders with an average diameter of more than 44 μm consist entirely of crystalline phases, and are therefore crystalline single-phase alloy powders.

When each powder was subjected to Auger analysis and component analysis, the results shown in FIG. 2 and Table 2 were obtained.

In FIG. 2, line A indicates the amount of oxygen gas in the amorphous single-phase alloy powder, and line B indicates the amount of oxygen gas in the crystalline single-phase alloy powder. In the shaded area of line A, al corresponds to the outer periphery of the amorphous single-phase alloy powder (corresponding to outer periphery 2 in Fig. 1), and therefore indicates that there is a layer in which oxygen gas is diffused. There is. In addition, a2 represents the amount of oxygen gas at the outer periphery. In line B, the shaded area as described above does not appear, so there is no layer in which oxygen gas is diffused in the outer periphery of the crystalline single-phase alloy powder. Does not exist.

Table ■ Next, as shown in Figure 3(a), the raw material powder, amorphous single-phase alloy powder 1a, was mixed with an aluminum alloy (AA standard).
6061 material) to form an aggregate 1, and the shrunken body 5 was placed in a vacuum chamber 7 with an opening 6 open. Then, inside the vacuum chamber, 3 x 10-
The aggregate 1 was heated to a temperature equal to or higher than its crystallization temperature Tx while the pressure was reduced to 5 Torr, and the aggregate 1 was subjected to a degassing treatment. Through this degassing process, most of the oxygen gas (and hydrogen gas) contained in the assembly 1 is exhausted, so the degree of vacuum in the vacuum chamber 7 decreases, but after a predetermined period of time, the degree of vacuum returns to the original level. 3 x 10-'T.

Since the temperature returned to rr, the heating state was continued until that point.

For example, when the heating temperature is set to 450°C, it has been confirmed that the original degree of vacuum returns to the original degree of vacuum in about 7 minutes after reaching that temperature. Further, by the degassing treatment, the amorphous single-phase alloy powder 1a is crystallized and changed into a crystalline single-phase alloy powder (for convenience, referred to as phase change alloy powder IC).

Next, the assembly 1 is cooled while introducing argon gas into the vacuum chamber 7, and when the temperature has dropped sufficiently, a stopper 8 is placed in the opening 6 of the contraction body 5, as shown in FIG. 3(b). The reduced body 5 was taken out from the vacuum chamber 7.

The operations described in step 2 are performed by varying the heating temperature during the degassing treatment, and then the inside of the glove box is maintained in an argon gas atmosphere, and the phase change alloy powder obtained by the degassing treatment is subjected to Auger analysis. I did it.

Line C in Figure 2 shows the amount of oxygen gas in the phase change alloy powder IC,
As is clear from line C, the shaded part of line A has almost disappeared, and this is because most of the oxygen gas that was present in the outer periphery of the amorphous single-phase alloy powder 1a has been exhausted. means that it has been done.

Table ■ shows the results of component analysis.

Table ■ As is clear from Table ■, in the amorphous single-phase alloy powder having the above composition, the heating temperature during degassing treatment was 400°.
It can be seen that the oxygen gas discharge effect occurs at temperatures above C.

In addition, in the crystalline single-phase alloy powder shown in Table I, no oxygen gas discharge effect was observed due to the degassing treatment.

(Example I) Amorphous single-phase alloy powder with an average diameter of less than 22 μm having a composition of A j2ssN i s Ys Co z (values are atomic %) (oxygen gas amount 0.14% by weight, crystallization temperature Tχ299.5 °C) was selected as the raw material powder.

As shown in FIG. 4, a die 11 with an inner diameter of 30 mm is installed in the vacuum chamber 10 of the real press device 9, and the raw material powder 1a is put into the die 11 to form an aggregate 1, and the vacuum chamber 10 is vacuumed. The aggregate 1 was heated to a temperature equal to or higher than its crystallization temperature Tx by the heater 12 while the temperature was maintained at 3×10 −' Torr or less, and the aggregate 1 was subjected to a degassing treatment.

Next, the aggregate 1 was subjected to pressure molding treatment under conditions of a pressing force of 30 tons from the punch 13 and sintered, thereby obtaining various structural members 1 to (2).

The same operation is carried out with the raw material powder having the same composition as above,
Various structural members V to (2) were obtained by using crystalline single-phase alloy powder having an average diameter exceeding 44 μm.

When the density and strength of each of the structural members 1 to (2) were examined, the results shown in Table (2) were obtained.

Table ■ As is clear from Table ■, when an amorphous single-phase alloy powder is used as the raw material powder 1a and the aggregate 1 is degassed at 400°C or higher, a high-density and high-strength structure is formed. Part ■
,■ can be obtained.

The reason why such structural members (1) and (2) are obtained is as follows.

That is, by setting the heating temperature of the degassing treatment to 400°C or higher, the oxygen gas existing in the outer peripheral part 2 of the raw material powder 1a is oxidized when the oxide film 3 exists on the outer surface of the raw material powder 1a. While the membrane 3 is crushed, the powder is discharged while moving from one powder to the other, thereby activating the outer surface of the raw material powder 1a. When the aggregate 1 of the raw material powder 1a is subjected to pressure molding under these circumstances, the outer surfaces of the activated powders come into close contact with each other, creating a neck (contact) between them. This makes it possible to sufficiently bond the raw material powders 1a to each other.

Such a phenomenon does not occur when crystalline single-phase alloy powder is used as the raw material powder.

Figure 5 is a micrograph (magnification) showing the metallographic structure of a structural member, and the same figure (a) at a magnification of 10.000 times shows the case where the amorphous single-phase alloy powder is used as the raw material powder, and the image at a magnification of 1
, 500 times the same figure (b) corresponds to the case where the above-mentioned crystalline single-phase alloy powder is used as the raw material powder.For both members, the pressing force of the punch is 10 tons, and the pressure forming start temperature is 450°C.
Manufactured under the following conditions.

Comparing Figures 5(a) and 5(b''), it is clear that in Figure 5(a) there is a neck part n between the raw powders 18, but in Figure 5(b) In the case of , the occurrence of neck part n is not recognized.

[Example ■]

Similar to Example I, Affi8SN is ya c Ox
(values are atomic %) with an average diameter of 22 μm
Amorphous single-phase alloy powder (oxygen gas amount 0.14% by weight)
, crystallization temperature Tχ299.5°C) was selected as the raw material powder.

As shown in FIG. 4, a die 11 with an inner diameter of 30 mm+ is installed in the vacuum chamber 10 of the hot press device 9, and the raw material powder 1a is put into the die 11 to form an aggregate 1, and the vacuum chamber 10 is maintained at a vacuum level. The assembly 1 is heated to 500°C by the heater 12 while maintaining the temperature below 3×10-'Torr.
The aggregate 1 was degassed.

Next, the aggregate 1 was subjected to pressure molding under conditions of a pressing force of 30 tons from the punch 13 and a pressure holding time of 1 hour to obtain a primary sintered body.

The density of the primary sintered body is 95% or more, especially the surface layer has a density of 10% or more.
It was close to 0% and almost no pores were observed.

Next, the primary sintered body was subjected to hot isostatic pressing (HIP) under conditions of 450° C., 2000 atm, and 1 hour to obtain a structural member.

The density of this structural member was approximately 100%, the tensile strength σ was 88 kgf/am'', and it was confirmed that it had approximately the same physical properties as a hot extruded material.

[Example ■]

Example ■Amorphous single-phase alloy powder with an average diameter of less than 22 μm having a composition of A2□Ni, Y, Co□ (values are atomic%) (oxygen gas amount 0.14% by weight, crystallization temperature T)
x 299.5°C) was selected as the raw material powder.

(i) As shown in FIG. 6(a), the raw material powder 1a is put into a rubber bell body 16 consisting of a main body 14 and a lid body 15, and then subjected to a cold isostatic press under a pressure of 4000 kgf/cd. (CIP) was applied.

(ii) As shown in the same figure, a diameter of 58 mm and a length of 40 m1. A short cylindrical green compact having a density of 78%, thus an aggregate l of raw material powder was obtained.

(ij) As shown in FIG. 2C, the aggregate I was loaded into a shrunken body 18 made of aluminum alloy (AA standard 6061 material). This reduced body 18 has an outer diameter of 78 mm and a length of 78 mm.
It consists of a main body 19 and a lid 20 welded to the opening of the main body 19, and the lid 20 has a ventilation pipe 21 that communicates the inside and outside of the main body 19.
7 (1v) As shown in FIG. 7(d), the aggregate 1 together with the contracted body 18 is transferred to the container 23 of the single-acting hot extrusion processing machine 22.
loaded into. In this case, the vent pipe 21 passes through the die hole 25 of the die 24 and extends into the die cutter 26 .

In the hot extrusion processing machine 22, the maximum pressing force was set to 500 tons, the inner diameter of the container 23 was set to 80 m1, and the preheating temperature of the container 23 was set to 470°C.

Next, a vacuum pump 27 was connected to the ventilation pipe 21 via a rubber pipe 28 to reduce the pressure inside the compressed body 18. When the degree of vacuum in the compacted body 18 exceeded 10-' Torr, the stem 29 was advanced to apply a load of about 120 tons to the housing 18 via the dummy block 30. As a result, the adult body 18 deforms and comes into close contact with the container 23, so that the temperature of the aggregate 1 rapidly rises and reaches 450° C. in about 7 minutes.

This heating and depressurization action degasses the aggregate 1, and the degree of vacuum inside the aggregate 18 decreases due to this degassing, but after the temperature of the aggregate 1 reaches 450°C, approximately 7
Minutes later, the temperature returned to above 10-5 Torr.

The holding time at this temperature varies depending on the density, composition, structure, etc. of the aggregate 1, but is set to 1 minute to 2 hours. In this production example, the degree of vacuum inside the compact 18 is 10-'To
When the temperature returned to rr, the aggregate 1 was extruded together with the compact 18, and the powders were sintered to obtain a round bar-shaped structural member (2). In this case, three types of structural members (2) were manufactured by changing the diameter of the die hole 25 and the extrusion pressure.

Also, as a raw material powder, AI! *Mixed-phase alloy powder with an average diameter of less than 22 μm and having a composition of zFes Ys (values are atomic%) (oxygen gas amount 0.15% by weight, crystallization temperature T
x 3 B 4.2°C), and three types of round rod-shaped structural members X were obtained under the same conditions as above.

Furthermore, as a raw material powder, 89% by weight A! , 6% by weight Cr
A rapidly solidified alloy powder (crystalline single-phase alloy powder, oxygen gas amount: 0.27 wt%) with an average diameter of less than 22 μm and having a composition of , 2 wt% Zr, and 3 wt% Fe was selected, and it was heated under the same conditions as above. Three types of round bar-shaped structural members XI were obtained as comparative examples.

Table (2) compares the manufacturing conditions and physical properties of various structural members (1) to (XI).

As is clear from Table ■, structural members ■, X according to the present invention
In this case, since the destruction occurs inside the powder,
Bonding at the powder interface due to degassing is sufficiently performed without being affected by changes in the diameter of the die hole 25, and hence changes in processing ratio, and high strength is achieved.

On the other hand, in structural member XI, which is a comparative example, when the processing ratio is low, the bonding at the powder interface is not sufficiently performed, resulting in low strength, and even when the processing ratio is high, structural members IX, The strength is significantly lower than that of This is because the amount of oxygen gas does not change before and after processing, and therefore, in the comparative example, the degassing effect in the present invention does not generate total heat.

[Example ■]

Similarly to Example 2, an amorphous single-phase alloy powder with an average diameter of less than 22 μm and having the composition A1@sN i5 YB CO2 (values are atomic %) (oxygen gas amount 0.14% by weight, crystallization temperature T x 299. 5°C) was selected as the raw material powder.

(i) As shown in FIG. 7(a), about half of the raw material powder 1a was put into a compact 31 made of aluminum alloy (AA standard 6061 material). The dimensions of this adult body 31 are an outer diameter of 78 mm, an inner diameter of 58 m+, a length of 200 m, and a thickness of 20 m.
It is m.

(ii) As shown in Figure (b), the compact 31 is placed in the die 32, and the raw material powder 1a is pressed with a pressure of 160 kgf/wm'' by the punch 33 to give a density of 95%.
The green compact, and therefore the aggregate 1, was molded.

As shown in FIG. 3C, the adult body 31 was machined to have a length substantially equal to the length of the aggregate 1.

The dimensions of the aggregate are 60 mm in diameter and 40 mm in length, and the dimensions of the adult body 31 are 78 mm in outer diameter and 60 mm in length.

(ji) This aggregate 1 was loaded into the container 23 of the single-action hot extrusion processing machine 22 shown in FIG. 6, with the bottom wall of the adult body 31 positioned on the front side in the extrusion direction. In this case, the preheating temperature of the container 23 was set to 470°C.

Next, the stem 29 was advanced to apply a load of about 200 tons to the adult body 31 through the dummy block 30. As a result, the adult body 31 deforms and adheres closely to the container 23, so the temperature of the aggregate 1 rises rapidly, and the temperature rises to 450 degrees in about 7 minutes.
reach °C. Immediately thereafter, the aggregate 1 was extruded together with the compact 31, and the powders were sintered to obtain a round bar-shaped structural member.

This structural member has pores due to residual hydrogen gas due to not performing degassing treatment under vacuum, so its tensile strength σ6 is approximately 62 kgfl■2,
Although the oxygen gas amount was lower than that of structural members IX and X obtained in Example ①, the amount of oxygen gas was the same as those of structural members IX and X. This means that oxygen gas is removed even if it is not under vacuum.

C1 Effects of the Invention According to the present invention, by using the raw material powder specified as described above, and by discharging oxygen gas and performing pressure molding in the sintering process, a high-density product with sufficient bonding between the powders is produced. A strong structural member can be obtained.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the raw material powder, Figure 2 is an Auger analysis diagram,
Figure 3 is an explanatory diagram of the degassing process, Figure 4 is an explanatory diagram of the hot press equipment, Figure 5 is a micrograph showing the metal structure of the structural member, Figure 6 is an explanatory diagram of the manufacturing side of the structural member, and Figure 7 is an explanatory diagram of the manufacturing side of the structural member. The figure is an explanatory diagram of the forming process of the aggregate. l...Aggregation, 1a...Raw material powder, 2...Outer periphery, 9...Hot press device, 22...Hot extrusion processing machine Figure 1 Figure 2 Shallow ← From the powder surface a Saichi → deep Fig. 3 (a) (b) Fig. 4 Fig. 5 (b)

Claims (1)

[Claims] In producing a high-strength structural member by sintering the raw material powder (1a), the raw material powder (1a) may be an amorphous single-phase alloy powder or a mixed-phase alloy powder containing an amorphous phase and a crystalline phase. , and a supersaturated solid solution powder having a composition similar to an amorphous phase forming composition, using an alloy powder in which oxygen gas is diffused in the outer peripheral part (2), and in the sintering step, A method for manufacturing a high-strength structural member, characterized in that the oxygen gas is discharged from the aggregate (1) of the raw material powder (1a), and the aggregate (1) is subjected to a pressure molding process.