JPS61270376A - Wear resistant al alloy member - Google Patents

Abstract

PURPOSE:To obtain an Al alloy member having excellent wear resistance by forming the composite phase consisting of an Ni-Al intermetallic compd. phase and hard carbide phase on the surface of an Al alloy base material in a desired part and specifying the concns. of the Ni and hard carbide layer in the composite phase. CONSTITUTION:The mixture composed of 1 or >=2 kinds of the hard carbides selected from TiC, WC, VC, ZrC, NbC and TaC and Ni is thermally sprayed onto the surface of the Al alloy base material in the position where the wear resistance is required to coat said surface. High-density energy such as TIG arc is then irradiated to said surface to heat quickly the surface for a short period and to melt and alloy part of the Ni+hard carbide coating layer and the Al alloy base material on the underside thereof by which the composite phase consisting of the Ni-Al intermetallic compd. phase and the hard carbide phase is crystallized in the Al alloy matrix. The conditions for irradiating the high-density energy are adequately set so that the average concn. of Ni in the composite phase attains 10-20wt% and the average concn. of the hard carbide phase attains 0.5-30wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is suitable for use in areas where wear resistance is required, such as valve seats in automobile engines.
2 alloy members, in particular, aluminum alloys that are alloyed with other materials on the surface of the Al alloy base material using a high-density energy source such as a laser beam or TIG arc to form a surface alloyed layer with high wear resistance. The market is related to alloy parts.

As is well known in the art, Al alloys are much lighter than commonly used iron-based materials, have excellent thermal conductivity, and have excellent support resistance, so they have recently been used in automobiles, etc. It has come to be widely used as various mechanical parts. However, Al alloys generally have inferior wear resistance compared to iron-based materials, and this has been a major obstacle when replacing iron-based members with Al alloy members for the purpose of reducing the weight of automobiles and the like.

Therefore, as a measure to improve the wear resistance of A2 alloy parts used in areas where wear resistance is required, surface treatments such as plating, anodizing, or thermal spraying have been applied to create a highly wear-resistant surface treatment layer. However, in all cases, the adhesion of the surface treatment layer to the base material was insufficient, and the drawback was that sufficient durability could not be ensured when used under high surface pressure.

From this point of view, the present applicant has already filed a patent application filed in 1986-78.
In No. 996, the surface of an Al alloy base material is coated with a mixed powder of N1 and hard ceramic particles, and high-density energy such as TIG arc or laser beam is irradiated to alloy the Al alloy base material and the mixed powder ( Aroink) Let me, N! 3
Ai', N iAl, N 12Al3, N iAi'3
proposed a method of forming a composite layer on the surface of an Al alloy member, in which hard ceramic particles are dispersed in a matrix made of a Ni-Al intermetallic compound.

Problems to be Solved by the Invention According to the proposed method, it is possible to form a composite layer with excellent wear resistance on the surface of an Al alloy member using an alo ink using a high-density energy source, and also to form a composite layer with excellent wear resistance on the surface of an Al alloy member. Since the matrix N1-Affiff Kazama compound is integrally bonded to the base Al alloy, it has high durability even under high surface pressure. However, one problem with the above proposal is that the entire matrix (base composition) of the composite layer is a Ni-Al intermetallic compound phase, and although this intermetallic compound phase has high hardness, it is extremely brittle, so alloying treatment is This inevitably causes the problem that subsequent processing is difficult. In other words, generally speaking, the surface after alloying treatment (the surface of the post-metal layer) inevitably has irregularities, so it cannot be used as is for machine parts such as valve seats, so in order to achieve surface accuracy, it is usually It is necessary to polish after alloying treatment, and in some cases, it may also require grinding, but as mentioned above, the composite layer with only intermetallic phase as a matrix is brittle, so polishing or grinding is not necessary. Chipping and cracks may occur during processing, making processing difficult.
Therefore, there were problems in using it as a practical material.

This invention was made against the background of the above-mentioned circumstances, and solves the problems of the above-mentioned proposal, and achieves remarkable wear resistance even under high surface pressure and high temperature conditions without causing difficulties in processing after alloying treatment. The purpose of this invention is to provide an Al alloy member with excellent properties.

Means for Solving the Problems The Al alloy member of the present invention has N on the surface of the AJ2 alloy base material.
1 as well as hard carbides, such as TiC (titanium carbide), WC (tungsten carbide), VC (vanadium carbide), zr
c (zirconium carbide), NbC (niobium carbide), Ta
By simultaneously alloying one or more selected from C (tantalum carbide), a hard carbide phase is dispersed in the surface layer to further improve wear resistance, and in the alloying, In order to prevent the entire base structure of the finally obtained alloyed layer (composite layer) from becoming a Ni-Al intermetallic compound phase, in other words, the Ni-Al intermetallic compound phase and the Al alloy phase are mixed. The average Ni degree in the layer is set so as to form a composite layer with a similar structure, thereby solving the problem of Ni-All alloyed compound phase brittleness as proposed above and ensuring workability. is.

Specifically, the wear-resistant 1 alloy member of this invention is suitable for use in areas where wear resistance is required! Ti on the surface of the alloy base material
C, WC, VC, ZrC, NbC.

By alloying N1 with one or more carbides selected from TaC, xl-Al intermetallic compounds and carbide hard phases are crystallized in the Al alloy matrix, and the average Nl concentration is 10. It is characterized by forming a composite layer on the surface of an Al alloy base material with an average concentration of carbide hard phase of Q and 5 to 30% by weight.

Function: The alloy member of the present invention is produced by alloying hard carbides such as Ni and TiC on the surface of the A2 alloy base material using a high-density energy source (alloy ink) as shown in the previous example. A composite layer in which Nr-p, i-based intermetallic compound and carbide hard phase are crystallized, that is, a composite layer in which Al alloy phase, Ni-Al intermetallic compound phase and carbide hard phase are mixed is formed. is.

Here, the Ni-Al intermetallic compounds are mainly N1Aff3 and N! 2 Two types of compounds of Al3 crystallize. That is, usually the average Ni in the composite layer
When the concentration is 28% by weight or less based on the total weight of Ni and Al, N1Af3 is crystallized, and when it is 28% by weight or more, N1AN3 and N12Aj'3 are crystallized. All of these N1-AJ2-based intermetallic compounds have high hardness and function to enhance wear resistance and heat resistance. In addition, carbides such as TiC, WC, VC, ZrC, NbC, and TaC are of course extremely hard, and therefore one or more carbide hard phases selected from these are finely dispersed and crystallized. plays the role of further improving wear resistance.

On the other hand, the Al alloy matrix phase in the composite layer is mainly composed of α-Al phase containing various solid solution elements as described later, and since this α-Al phase is soft, it is the main component of the entire composite layer. Acts to improve workability. That is, Ni-
Al'-based intermetallic compound phase and carbide hard phase and Af1f
By coexisting with the gold matrix phase, excellent wear resistance and heat resistance are obtained, and at the same time, the base structure is N1-A.
Much better workability can be obtained compared to the case of only the flf intermetallic compound phase.

In addition, the present inventors have already in another patent application alloyed only N1 on the Af1f gold base material surface without adding carbide,
We have proposed an Al alloy member in which a composite layer is formed in which a Ni-Al intermetallic compound is crystallized in an Al alloy matrix and the average Ni 1 degree is 10 to 40% by weight. In contrast, in the present invention, the hard carbide is also alloyed to crystallize the carbide hard phase, thereby further improving the wear resistance.

However, if the average Ni1 degree in the composite layer exceeds 40% by weight, the entire composite layer will consist only of the N1-Affif intermetallic compound phase, making the composite layer brittle and difficult to process. On the other hand, when the average N1 concentration in the composite layer is less than 10% by weight, the amount of N1-Af gold intermetallic compounds crystallized becomes extremely small, and the proportion of the Al alloy phase becomes relatively large, resulting in When the material of the part (for example, CO-Qr gold alloy used as a valve material) is used as a mating material, adhesion occurs due to friction, making it unsuitable as a wear-resistant member for use in the friction part. Therefore, the average degree of Nis in the composite layer needs to be within the range of 10 to 40% by weight. Furthermore, if the average concentration of the carbide hard phase in the composite layer is less than 0.5% by weight, the effect of improving wear resistance by adding hard carbide will not be sufficiently exhibited; If it is exceeded, the aggressiveness of the opponent becomes high and the wear of the opponent member increases.

Therefore, the average concentration of carbide hard phase in the bonding layer is 0.5
It was set within the range of ~30%.

Note that as the Al alloy base material, any A2 alloy used for mechanical parts etc. can be used.

Also, in the above explanation, N1-A! The parts other than the intermetallic compound phase were collectively referred to as the Al alloy matrix phase, but depending on the composition of the Al alloy used as the base material, it may actually include not only the α-8 phase in which various alloying elements are dissolved, That α-A
Of course, there will be problems if Mca-1'-based compounds or Cu-Al-based compound phases are crystallized in the I phase.

Furthermore, the composite layer as mentioned above is! Base material surface layer and Ni
Because it is formed by alloying with, to! Adhesion to the base material portion of the base material is sufficient, and therefore exhibits high durability even under high surface pressure.

In manufacturing the above-mentioned Al alloy members, first, the Al alloy parts of the parts where wear resistance is required are removed.
The alloy substrate surface is coated with a mixture of hard carbides such as Ni and TiC. Examples of coating methods include thermal spraying,
A plating method, a slurry coating method, or the like can be used. After forming the Ni-1+ hard N carbide coating layer in this way, the surface is irradiated with high-density energy such as TIG arc, laser beam, or electron beam to rapidly heat it for a short time to form an N1+ hard carbide coating layer and its surface. Lower Al
A part of the alloy base material (to a required depth) is melted and alloyed. In this alloying, in order to keep the average Ni concentration in the alloyed layer (composite layer) within the range of 10 to 40% by weight, the Al
It is important and necessary to appropriately set high-density energy irradiation conditions (output, relative movement speed between the base material and the energy source, etc.) so that the melting depth of the alloy base material is an appropriate depth.

Examples Example 1 JISAC2B known as aluminum alloy for castings
Al alloy (Cu 3.10%, 3i, 32%, Mg0
．． 34%, Zn0.01%, Fe0.43%, MnO,
6omm x 25mm x 8 consisting of 30% and balance Al
Ii as shown by symbol A in Table 1 on the surface of the mm specimen.
l! After thermal spraying Ni powder 75 heavy powder 7 lower powder, the thermal sprayed layer and the base material Al alloy were alloyed by TIG arc under conditions such that the average N1 permeability was in the range of 10 to 40% by weight. After polishing the surface of the composite layer formed by alloying, the specimen was finished in a size and shape suitable for human rapid wear testing. Afterwards, we conducted a rapid human wear test and analyzed the composition of the composite layer.

In addition, when a mixed powder of N1 powder and WC powder is used as the mixed powder to be alloyed, as shown by symbol B in Table 1, and when a mixed powder of N1 powder and VC powder is used, as shown by symbol C. , when a mixed powder of Ni powder and ZrC powder is used, as shown by the symbol E, when a mixed powder of N1 powder and NbC powder is used, as shown by the symbol F, and when a mixed powder of Ni powder and ZrC powder is used, as shown by the symbol F. and a case where a mixed powder of Ni powder, TiC powder, and WC powder is used as shown in @G,
In each of the above cases, as shown in @H, a mixed powder of Ni powder, VC powder, and ZrC powder is used, and as shown in symbol I, a mixed powder of N1 powder, VC powder, and NbC powder is used. Alloying was performed under the same conditions as above, and then subjected to multi-layer wear tests and compositional analysis.

The results of component composition analysis of the composite layers in the Al alloy members of Examples A to (1) above were as shown in Table 1.

Table 1 On the other hand, comparative material 1 is an iron-based sintered material (C0.7
0-1.20%, Mo4. , O~6.5%, C07~1
0%, Pb10-22%, balance Fe), and as a comparison material 2, only N1 was alloyed by TIG arc on the surface of the JIS AC2B Al alloy base material, and the weight%
An Al alloy member was prepared in which a composite layer having a composition of Al-34%N1-5%3i-2%Cu was formed.

The human rapid abrasion test results for these invention example materials A to ① and comparative materials 1 and 2 are shown in FIG. The test conditions for the human-sensitive rapid abrasion test are as follows: 5UH1 1
and the final load6. 3kg, sliding speed 0.31m
/Sec, and the sliding distance was 100 m.

From FIG. 1, in the case of embodiments A to D according to the present invention,
Compared to Comparative Material 1, which is a conventional valve seat material, the wear scar area in the human rapid wear test is smaller, and it has better wear resistance than the conventional Comparative Material 1, and is alloyed only with N1. It is clear that the wear resistance is superior to Material 2.

Here, the Ni concentration of the example material of this invention and the N of comparative material 2
1 concentration is approximately equivalent, therefore Ni and Ti simultaneously
It is clear that the wear resistance was further improved by alloying C and other hard carbides.

In the above examples, no cracks or chipping occurred during the polishing process after the alloying process.
We were able to perform the polishing process smoothly.

Furthermore, when the structure of the composite layer of the example material of the present invention was observed using an optical microscope and EPMA, it was found that N was present in the α-8 phase as the Al alloy matrix phase.
It was confirmed that N1Affi3 and/or N i 2 Al3, which are i-Al based intermetallic compounds, were uniformly distributed and a fine carbide hard phase was uniformly dispersed and crystallized.

Example 2 As the mixed powder to be alloyed, a mixed powder of pure Ni powder and TiC powder was used, a mixed powder of pure N1 powder and WC powder was used, and a mixed powder of pure N1 powder and VC powder was used. When using a mixed powder of pure Ni powder and ZrC powder, when using pure N1 powder and NbC powder, and when using a mixed powder of pure N1 powder and TaC powder, N1 alloyed composite layers with various amounts of carbide hard phase were prepared by changing the amount of carbide powder in each case.
1 surface. Other alloying conditions are the same as in Example 1. In addition, when mixed powder containing any carbide is alloyed, the N1 concentration in the composite layer is 30 ± 5% by weight.
I'll go.

FIG. 2 shows the results of a human rapid wear test conducted on the composite layers of Al alloy members having various amounts of carbide obtained as described above, depending on the amount of carbide.

Note that the test conditions in this case are the same as in Example 1.

On the other hand, the aggressiveness of each Al alloy member composite layer to a mating material during friction was investigated as follows. In other words, the rotor of the human-sensitive rapid wear test is made of an Al alloy member with a composite layer formed as described above, and the plate is made of JIS standard 5UHI.
The aggressiveness of the composite layer was evaluated using the wear scar area of Pre=1 using L material. The results are shown in FIG.

As is clear from Figure 2, the carbide storage in the composite layer is 0.5
It can be seen that if the amount is less than % by weight, the wear scar area of the composite layer is large and sufficient wear resistance cannot be obtained.

As the amount of carbide increases, the wear scar area of the composite layer decreases and the wear resistance improves, but as shown in Figure 3, if the carbide content in the composite phase exceeds 30% by weight, the aggressiveness of the opposing material decreases. You can see that it increases. Therefore, in this invention, as already mentioned, the amount of carbide in the composite layer is set in the range of 0.5 to 30% by weight.

Example 3 When only pure Ni powder is used as the mixed powder to be alloyed, when a mixed powder of pure Ni powder and TiC powder is used, when a mixed powder of pure Ni powder and WC powder is used, and 1lTl! In the case of using a mixed powder of Ni″l/fJ powder and VC powder, alloying was performed so that the Ni of the composite layer after alloying was changed.Other conditions were as in Example 1. Same as , it is necessary. Note that N
In the case of i powder + TiC powder, the TiC concentration in the composite layer is 4
±2% by weight, W in composite layer in case of Ni powder + WC powder
The C concentration is 10±2% by weight, and the VC concentration in the composite phase in the case of Ni powder + VC powder is 5±2% by weight.

The wear resistance of the Al alloy member composite layer was investigated using a human rapid wear test in the same manner as in Example 1.
It is shown in FIG. 4 corresponding to yA degree. From FIG. 4, it can be seen that when the N1 concentration is 10% by weight, optical wear resistance cannot be obtained.

Effects of the Invention As is clear from the above explanation, the Al alloy member of the present invention has hard carbides such as Ni and TiC alloyed on the surface of the Al alloy base material, and Ni-, L in the alloy gold matrix.
' series gold intermetallic compound and carbide hard phase were crystallized to form a composite layer with an average Ni concentration of 10 to 40% by weight and an average concentration of the carbide hard phase in the range of 0.5 to 30% by weight. Since it is monodore, it has high wear resistance and heat resistance as well as good workability, so it can be used in areas where wear resistance is required under high surface pressure and high temperature conditions. It has the advantage that it can exhibit durability and can easily be subjected to polishing or grinding for application to actual parts.

Hence this invention! The alloy member is suitable for application to, for example, a valve seat of an Al alloy cylinder head, a claw portion of an Al alloy shift fork, an Al alloy cylinder liner, an Al alloy rocker arm pad, and the like.

[Brief explanation of the drawing]

FIG. 1 shows Example material A-I in Example material 1 of this invention.
Graph showing the wear test results of Comparative Material 1.2 and Comparative Material 1.2, 2nd
The figure is a graph showing the effect of carbide concentration in the composite layer on wear resistance in Example 2, and Figure 3 is the same. Figure 4 shows the N in the composite layer in Example 3.
3 is a graph showing the influence of i concentration on wear resistance. Applicant Toyota Motor Corporation Representative Patent Attorney Yutaka 1) Hisashi Take (and 1 other person) Figure 3 Figure 4 N1 amount (wt%) ψ 0 〉 ○ (0 × 9 ψ dimension ('J Oh please

Claims (1)

[Claims] T is applied to the surface of the Al alloy base material in areas where wear resistance is required.
By alloying Ni with one or more carbides selected from iC, WC, VC, ZrC, NbC, and TaC, the Ni-Al intermetallic compound phase and the carbide hard phase can be converted into an Al alloy. A composite layer having an average Ni concentration of 10 to 40% by weight and an average concentration of a carbide hard phase of 0.5 to 30% by weight by crystallization in a matrix is formed on the surface of an Al alloy base material. Abrasive Al alloy member.