JP2001001265A - Aluminum alloy member, surface treatment method for the same, cylinder block and its surface treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment method to easily impart the wear resistance to a sliding member formed of an aluminum alloy at a low cost. SOLUTION: This surface treatment method includes a step in which ceramic particles 3 are diffused on a surface layer part of a bore inner surface 21 to form a fixed reformed layer 4 by blowing and colliding the ceramic particles 3 of 150 μm or under in grain size against the bore inner surface 21 of a cylinder block 20 formed of an aluminum alloy, and a step in which the surface finish is executed on unevenness 10 formed on the surface of this reformed layer 4 through the rolling operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aluminum alloy sliding member having excellent wear resistance by subjecting a surface of a sliding member made of an aluminum alloy such as a cylinder block to blasting.

[0002]

2. Description of the Related Art Conventionally, sliding members formed of an aluminum alloy have been subjected to surface treatment such as plating and thermal spraying, and a coating having wear resistance is formed on the surface of the sliding member by these methods. By doing so, the wear resistance of the sliding member is improved. However, in such surface treatments such as plating and thermal spraying, the yield of the coating material is poor and the treatment time is long. In addition, since the process of forming the surface treatment film is complicated as shown in FIG. 5, it cannot be incorporated into a process in a production line of an object to be processed, and there is a problem that the processing cost increases. Furthermore, wet surface treatment has environmental problems such as waste liquid treatment.

A typical example of a sliding member made of an aluminum alloy is a cylinder block. As a method for imparting wear resistance to the inner surface of the bore of the cylinder block, in addition to the above-described plating and spraying, etc. Further, (1) a method of casting or press-fitting a sleeve made of cast iron on the inner surface of the bore, or (2) a cylinder block material made of an aluminum alloy material having excellent wear resistance, for example, a high Si material such as A390. However, these methods also have the following problems: (1) If a cast iron sleeve is used, the cost is low, but the cast iron sleeve is heavy, so (2) If the cast iron sleeve or plating is applied to an engine with a small load on the inner surface of the bore, such as a generator, the quality will be excessive. In addition, some low-power generators, etc., use an engine in which the inner surface of the bore is subjected to rolling only with rollers without special surface treatment, but there is a problem in terms of durability, (3) Furthermore, when an aluminum alloy material with excellent wear resistance is used as the material for the cylinder block, it will be a sleeveless cylinder, similar to surface treatment such as plating, so it is possible to reduce the weight. However, there is a problem that the cost is high because casting and machining are difficult.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a surface treatment method for easily imparting wear resistance to a sliding member made of an aluminum alloy at low cost. I do.

[0005]

In order to achieve the above-mentioned object, a method for treating the surface of an aluminum alloy member according to the present invention comprises spraying ceramic particles and causing the particles to collide with the surface of the aluminum alloy member. Is a method of forming a modified layer in which the above-mentioned ceramic particles are dispersed and fixed on the surface layer portion. The ceramic particles or powder having a particle size of 150 μm or less, that is, a mesh # 100 or more is used. Among them, the particle size is 5 μm
It is preferable to use one having a particle diameter of 1 to 106 μm.
It is more preferable to use 0 μm to 90 μm. As the material of the ceramic, glass, alumina, SiC or the like can be used, and among them, glass is particularly preferable. One type of ceramics may be used, or two or more types may be mixed and used. The injection pressure of ceramic particles is 3k
gf / cm ² or more. Of these, 3 to 10 kgf /
cm ² is preferable, and 4 to 8 kgf / cm ² is more preferable. The injection time is not particularly limited by the ceramic particle diameter or the injection pressure of the particles.
Seconds / mm ² are preferred.

Further, the surface treatment method according to one aspect of the present invention is characterized in that the ceramic particles having a particle size of 150 μm or less are sprayed and made to collide with the surface of the aluminum alloy member so that the surface layer of the aluminum alloy member is The method includes a step of forming a modified layer in which ceramic particles are dispersed and fixed, and a step of subjecting the surface of the modified layer to surface finishing by rolling. The rolling process is a process for improving the hardness by pressing a modified layer formed on a surface layer of an aluminum alloy member into a dense structure by using a roller, a plate, or the like. In addition, by this rolling, an oil sump can be formed on the surface of the aluminum alloy member by crushing the aluminum alloy member while partially leaving the irregularities formed on the surface. Then, as another aspect of the present invention, in the surface treatment method, glass particles having a non-angular shape can be used as the ceramic particles. If the shape of the ceramic particles to be sprayed is angular, the modified layer is formed on the surface of the object to be processed and the modified layer is ground at the same time, so that the formation of the modified layer becomes difficult to progress. On the other hand, a substantially spherical powder or particle having a non-square periphery has much less power to grind the surface of the workpiece when sprayed. Furthermore, the aluminum alloy member of the present invention is a member that has been subjected to a surface treatment by the above-described method of the present invention.

The surface treatment method of a cylinder block according to the present invention is characterized in that ceramic particles having a particle size of 150 μm or less are jetted and collided with the inner surface of the bore of the cylinder block made of an aluminum alloy. Forming a modified layer in which the ceramic particles are dispersed and fixed in the portion, and applying a surface finish by rolling to the surface of the modified layer.
The above surface treatment method can be applied to the inner surface of the bore of the cylinder block, and a lightweight and highly durable cylinder block can be easily manufactured at low cost. Further, since the blasting apparatus is simple and the number of blasting steps is small, it can be incorporated into a part of the production line including the preceding and following processing steps. In the cylinder block according to the present invention, ceramic particles having a particle size of 150 μm or less are sprayed and collided with the inner surface of the bore of the cylinder block made of an aluminum alloy, so that the surface of the inner surface of the bore is covered with the ceramic particles. The surface treatment is performed by a method including a step of forming a modified layer in which the modified layer is dispersed and fixed, and a step of performing a surface finish by rolling on the surface of the modified layer.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an aluminum alloy member, a surface treatment method for the aluminum alloy member, a cylinder block and a surface treatment method for the cylinder block according to the present invention will be described below in detail with reference to the drawings. Will be described.

[Material of Workpiece] The workpiece used in the present invention is suitably a member having a relatively low melting point, for example, an aluminum alloy member. This is because the blasting process causes the ceramic particles to collide with the object to be processed, and the heat generated at the time of the collision forms a reformed layer in which the ceramic particles are incorporated into the surface layer of the object to be sufficiently softened. Alternatively, a material that melts is preferable. In contrast, when blasting is applied to high melting point materials such as iron-based metals,
Although the structure of the surface layer of the object to be processed can be changed by the effect of heat generated at the time of collision, it is insufficient to melt the surface layer, and it is necessary to form a modified layer incorporating the ejected particles. I can't.

[Ceramic Particles] The ceramic particles used in the present invention are gradually pulverized by the impact when sprayed onto the object to be processed, and partly become extremely fine particles, for example, powder having a particle diameter of 10 μm or less. As a material of the ceramics, glass, alumina, SiC, and the like are very hard and have excellent wear resistance, but have characteristics of being brittle. The ceramic particles actually incorporated into the modified layer are fine particles, and when such particles are incorporated, a dense and uniform modified layer can be obtained. In the present invention, powders that are more easily crushed at the time of injection have a greater effect, and glass is particularly desirable. At this time, if the particles to be sprayed are fine powders of 10 μm or less from the beginning, not only the fluidity of the powders in the blasting device is deteriorated, but also the cost is increased, so that the particles having the large particle size and the small particles Can also be used as a mixture. However, from the viewpoint of production, it is better to use a mixture of fine particles that are pulverized and large particles that have not been pulverized by using particles of a size almost uniform from the beginning. It is desirable because it is easy to manage. On the other hand, when it is intended to obtain the same effect as the present invention by spraying metal powder, it is necessary to use fine powder because the metal is hard to be crushed at the time of collision,
It is industrially unfavorable because special equipment is required.
On the other hand, as described above, the ceramic powder can be automatically made finer and taken in at the time of injection without using particularly fine powder. Further, in order to improve the wear resistance, ceramics harder than metal are more effective, and two or more types of ceramic particles of different materials may be mixed and sprayed according to the application.

[Shape of ceramic particles to be sprayed] Usually, a pre-treatment is performed before spraying or the like. When a blast treatment is performed as the pre-treatment, the blast material is used to grind the surface of the workpiece. Use angular shaped particles like crushed powder. However, when the crushed powder is sprayed in the present invention, the modified layer is formed on the surface layer of the object to be treated and the modified layer is ground at the same time, so that it is difficult to form the modified layer, which is not preferable. On the other hand, when spherical ceramic particles such as beads collide with the object to be processed, the object of the present invention promotes heat generation on the surface of the object to be processed and more effectively than grinding the surface of the object to be processed. The surface can be softened or melted. At this time, the ceramic particles that collided with the surface of the workpiece are gradually pulverized from the outside and chipped, but the chipped fine particles have no grinding power and are taken into the modified layer, and the other particles Functions to soften or melt the surface of the object to be treated and form a modified layer. Therefore, the non-square, substantially spherical powder can form the modified layer more quickly.

[Particle Size of Injected Particles] When the diameter of the ceramic particles to be injected is small, the kinetic energy of the particles increases because the individual particles move at a high speed when injected. The thermal energy generated when colliding with the surface increases. Because the heat energy can soften or melt the surface of the object,
The particles to be sprayed can be taken into the surface layer of the object. On the other hand, if the particle size is large, the generated thermal energy is not enough, so that it becomes difficult to sufficiently soften or melt the surface of the object to be treated, and it is not possible to form the modified layer. Here, the particle size means the average particle size, and the average particle size is 3% from the average particle of the largest particle.
It is determined from the average diameter of the 0th particle and the average diameter of the three particles. For example, fine particles having an average particle size of 80 μm
According to R6001, "the average diameter of the largest particle is 171 μm or less, and the average diameter of the 30th particle from the largest particle is 120 μm.
Hereinafter, the average of the average diameters is 87.5 to 73.5 μm ”. Therefore, in the present invention, in order to obtain a modified layer that contributes to improving the wear resistance of the sliding member, the particle size is set to 150 μm or less (mesh # 100 or more). As mentioned above, this particle size is preferably between 5 and 106 μm, more preferably between 10 and 106 μm.
９０90 μm.

[Blasting process] Usually, the blasting process
It is used for pre-treatment when performing surface treatment such as thermal spraying, and for deburring products generated by cutting. In the pretreatment of this thermal spraying, the particle size is 250 to 450 μm.
As shown in FIG. 1, the blast material particles are often used. However, as shown in FIG. 1, the blast material particles 2 penetrate into the surface of the workpiece 1 by the blast treatment. No. 2 is present as a foreign substance between the base material as the workpiece 1 and the sprayed coating, and the adhesion of the sprayed coating is reduced. On the other hand, in the present invention, fine ceramic particles having a particle size of 150 μm or less (mesh # 100 or more) are sprayed onto the aluminum alloy member as a base material, so that the ceramic particles collide with the aluminum alloy member. At the same time as the surface of the aluminum alloy member is softened or melted by the generated heat,
The above-mentioned ceramic particles are taken in, and then immediately cooled. As a result, as shown in FIG. 2, a modified layer 4 is formed in which the ceramic particles 3 are dispersed and fixed on the surface layer of the aluminum alloy member as the workpiece 1. Since the hard ceramic particles 3 are finely dispersed, the modified layer 4 is excellent in wear resistance, and the wear resistance is improved as the thickness of the modified layer 4 increases. Further, since the matrix of the modified layer 4 is the aluminum alloy itself as the base material, there is no problem such as cracking or peeling. Further, according to the blast treatment used in the present invention, the ceramic particles 3
Can be easily dispersed or mixed in the surface layer of the article 1 to be treated. For this reason, the processing time is short, and the processing is easy even when the shape of the processing target 1 is a curved surface or when the processing target surface has a large area. In addition, since the ceramic particles 3 that are not fixed to the surface of the workpiece 1 by the blasting process are continuously supplied to the blasting process until they are fixed without being discarded, the yield of the functional material is lower than that of a technique such as thermal spraying. Very good. Further, blast processing can be performed with simple equipment, and the cost is low.

[Differences between Other Blasting and Surface Treatment According to the Present Invention] By blasting or shot peening, particles are made to collide with the surface of the object to be treated, and the temperature of the surface is raised to a certain temperature or higher. Japanese Patent Publication No. 2-17607 discloses a method of changing the metal structure of the surface layer of the object to be processed to achieve the same effect as the heat treatment. However, the present invention does not raise the temperature of the surface of the processing target 1 to change the metal structure, but forms the modified layer 4 by dispersing the ceramic particles 3 in the surface layer portion of the aluminum alloy. In addition, since aluminum alloys have inherently low hardness, there is a limit to performing only heat treatment, and it is difficult to apply them to sliding parts exposed to severe sliding conditions. However, the present invention can be suitably used for a sliding member because the ceramic particles 3 which are very hard and have excellent wear resistance are dispersed on the surface of the aluminum alloy member and the wear resistance is greatly improved. Also, JP-A-8-3
No. 33671 describes a method of room temperature diffusion and permeation plating in which elements of a coated metal powder are diffused on the surface of an object to be treated. However, according to the present invention, the ceramic particles 3
In this state, the modified layer 4 dispersed and fixed on the surface layer portion of the processing object 1 is formed, which is basically different from the technique disclosed in the above publication.

[Dimension Finishing by Rolling] When the surface of the aluminum alloy member is subjected to blasting, FIG.
As shown in (1), since the unevenness 10 is formed on the surface, it is necessary to finish the dimensions to eliminate the unevenness 10 on the surface when used as a sliding member. As a dimensional finish, for example, there is a method of shaving the convex portion 10a formed on the surface of the modified layer 4 by cutting, but since the thickness of the modified layer 4 is limited, the modified layer 4 is left. It is difficult to perform a cutting process. On the other hand, since the hardness of the aluminum alloy member is low, as shown in FIG. 3B, when the unevenness 10 on the surface of the aluminum alloy member, which is the workpiece 1, is subjected to rolling by a roller 11 or a plate. The dimensional finishing can be easily performed while the modified layer 4 is left.
By this rolling, the structure of the modified layer 4 becomes denser and the hardness is improved, and the holdability of the ceramic particles 3 is improved. In addition, the dimensional finishing of the surface is performed by leaving only the concave portion 10b partially without losing all the unevenness 10 on the surface.
2 can be formed.

[Application to Cylinder Block] As shown in FIG. 4, if the above-described surface treatment method according to the present invention is applied to the cylinder block 20, after the ceramic particles 3 are sprayed on the inner surface 21 of the bore of the cylinder block 20, , Because the wear resistance can be improved only by rolling,
The lightweight and highly durable cylinder block 20 can be manufactured at low cost. Blasting device 3 shown in FIG.
0 is provided with a blast gun 31. The blast gun 31 is configured to be rotatable in the circumferential direction and to be capable of reciprocating linear movement in the axial direction. In addition, an injection hole 32 is provided at the tip, and particles are injected from the injection hole 32. Since the blast device 30 has a relatively simple structure and has a small number of surface treatment steps, it can be incorporated into the cylinder block manufacturing process including the preceding and following steps as shown in FIG. In comparison, as described with reference to FIG. 11, the manufacturing process of a general plating cylinder requires a very large number of steps and a long processing time. Furthermore, the plating process cannot be applied to a die-cast cylinder having many cavities, but the surface treatment according to the present invention can be applied.Moreover, in order to temporarily soften or melt the inner surface of the bore, it is possible to fill small cavities. it can.

[0017]

Next, the contents of the present invention will be described in more detail with reference to examples. [Example 1] A blast treatment was performed using the samples of the combinations shown in Table 1 to form a modified layer 4 on the surface layer of a test piece, and then the thickness and hardness of the modified layer 4 were measured. The cross-sectional structure was observed. First, the size of the processing surface is 20m
An aluminum alloy test piece measuring mx 40 mm was subjected to a blast treatment for spraying the respective ceramic particles 3. The injection conditions were an injection pressure of 5 kgf / cm ² and an extremely short injection time of 10 seconds. Next, the test piece after the blast treatment was cut, the thickness and hardness of the modified layer 4 formed on the surface layer of the test piece were measured, and the cross-sectional structure near the surface of the surface layer was observed. These results are shown in Table 1 and FIGS.

[Table 1]

In Example 1-1, a test piece having a material of ADC12 was used, and the ceramic particles had a particle size of 45 to 75 μm and a mesh number of # 2.
Twenty glass beads were used. The glass beads were jetted under the above-described conditions of pressure and time, and were caused to collide with a test piece. As a result of this collision, as shown in FIG. 6, very fine glass particles 40 are dispersed and fixed near the surface of the ADC12 material 39 serving as the base material, and the modified layer 4 having a thickness of about 17 μm is formed. Was. Since the glass particles 40 are very finely and densely dispersed in the modified layer 4, they do not fall off due to sliding on the member surface. Further, as shown in Table 1, it can be seen that the hardness of the modified layer 4 was higher than the base material of the test piece.

In Example 1-2, AC was used as a test piece.
A T6 treated product of 4C material 45 was used, and the same glass beads as in Example 1-1 were used. Also in this case, the modified layer 4 in which the glass particles 40 are dispersed is formed on the surface layer of the test piece as shown in FIG. 7, and the hardness of the modified layer 4 of the test piece is also reduced as shown in Table 1. It was higher than the hardness of the base material. In Example 1-3, the material of the ceramic particles was changed to alumina beads. However, since the particle size of the alumina beads was sufficiently small, Examples 1-1 and 1-2 were used.
In the same manner as in the case where the glass beads are sprayed, the modified layer 4 in which very fine alumina particles 46 are dispersed is formed as shown in FIG. 8, and the hardness of the modified layer 4 is also reduced as shown in Table 1. Increased. However, the thickness of the modified layer 4 was smaller than in Examples 1-1 and 1-2 when glass beads were jetted. This is because the modified layer 4 was formed quickly because glass is more brittle and easily crushed.

Example 1-4 is a case where the ceramic particles to be sprayed with respect to Example 1-3 are changed from alumina beads to crushed alumina powder. As shown in FIG. A similar modified layer 4 was formed, but its thickness was thin as shown in Table 1. This is because, at the same time as the modified layer 4 was formed, the crushed alumina powder scraped the modified layer 4 little by little. On the other hand, in the comparative examples, the sprayed glass beads used had a large particle size, similarly to those used in the conventional blast treatment. According to this, as shown in FIG. 10, the surface of the test piece was sufficiently rough, but the glass particles 50 were only penetrating into the very surface of the test piece, and the dense modified layer 4 was formed. Was not done. This is because the surface of the test piece was insufficiently softened or dissolved due to the large diameter of the particles to be sprayed. Further, since the glass particles 50 are only stuck into the surface of the test piece, the glass particles 50 fall off due to sliding on the surface of the member. rare.

Example 2 In order to confirm the wear resistance of the modified layer 4 of the aluminum alloy member obtained in the present invention,
A durability test using a generator engine was performed. FIG. 4 shows a state in which blast processing is performed on the bore inner surface 21 of the single cylinder cylinder block 20. First, the bore inner surface 21 (bore diameter φ60) of the cylinder block 20 made of the ADC 12 is used.
mm), the inner surface 21 of the bore was blasted by injecting the ceramic particles 3 while inserting the rotation type blast gun 31 obliquely downward from the head surface 22 side of the cylinder block 20. The ceramic particles 3 used the glass beads # 220 of Example 1-1, and the injection time was 90 seconds. Then, after blasting,
Using the roller 11, the oil sump 1 is partially formed in the bore inner surface 21.
A ceramic shot cylinder block A was finished, which was finished in dimensions to be subjected to rolling processing except for No. 2. The cylinder block A was assembled to a generator having the engine specifications shown in Table 2, and an engine durability test was performed under the conditions shown in the table. As a comparative example, without blasting,
A similar durability test was performed on a conventional cylinder block B in which only the rolling process was performed on the bore inner surface 21. Table 3 shows the amount of change in bore diameter before and after the durability test for these cylinder blocks A and B.

[Table 2]

[Table 3]

The conventional cylinder block B which had not been subjected to the blast treatment was stopped and disassembled because the output of the engine decreased 2.5 hours after the start of the test. This engine not only had galling between the bore inner surface 21 and the piston, but also had stepped wear on the bore inner surface 21 and had a bore diameter of at most 159.
μm was spread. On the other hand, in the cylinder block A according to the present invention, the output during the durability test is also stable, and the amount of change in the bore diameter after 10 hours from the start of the test is also one.
It was 0 μm or less. Further, the roughness of the bore inner surface 21 before the durability test was Ra = 1.5 and Rz = 7.2 by the rolling process.
As a result, there was no rise in oil or generation of blow-by gas. Further, the same durability test was performed on the cylinder block C that was subjected to only blasting on the bore inner surface 21 and was not subjected to the rolling process. However, immediately after the test was started, the test was stopped because of a large amount of oil rise. This is because the roughness of the bore inner surface 21 is Ra = 2.5, Rz = 13.
9, the oil leaked from the gap between the piston ring and the bore inner surface 21 into the combustion chamber.

As described above, by spraying ceramic particles having a particle diameter of 150 μm or less (mesh # 100 or more), the modified layer 4 in which the ceramic particles are dispersed and fixed on the surface of the aluminum alloy member is formed. I found out. The modified layer 4 has a shape in which the shape of the powder to be injected is not angular, preferably spherical, and the thickness of the material increases as the material is more easily crushed by the impact at the time of injection, such as glass. It turns out. And, in a sliding member made of an aluminum alloy, it has been found that this modified layer is very effective in improving the wear resistance of the sliding member. In particular, it is very effective to subject the sliding surface such as the inner surface 21 of the bore of the cylinder block 20 to dimensional finishing by leaving the oil pool 12 by rolling after blasting.

[0024]

According to the present invention, the following effects can be obtained. (1) The wear resistance of a sliding surface made of an aluminum alloy can be easily improved, and a sliding member can be manufactured without expensive surface treatment or using a special material. (2) For aluminum alloy sliding members that require dimensional finishing, blasting is performed, and then rolling is performed, so that the modified layer formed on the surface of the object to be processed is sufficiently left, while dimensional finishing is performed. Can be. Further, by the rolling process, the modified layer becomes denser and the hardness is improved, and the ceramic particles taken into the modified layer are reliably held therein.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a surface layer portion of an object to be processed which has been subjected to blast processing using particles having a large particle diameter.

FIG. 2 is a cross-sectional view showing a surface layer portion of an object to be treated which has been subjected to a surface treatment according to the present invention.

3 (a) is a cross-sectional view showing a surface layer portion of an object to be treated which has been subjected to the surface treatment according to the present invention, and FIG. It is sectional drawing which shows the surface layer part which processed.

FIG. 4 is a cross-sectional view of a cylinder block whose inner surface is subjected to surface treatment by the surface treatment method according to the present invention.

FIG. 5 is a flowchart showing a manufacturing process of a cylinder block in which a surface treatment process according to the present invention is partially incorporated.

FIG. 6 is a photograph with a magnification of 400 times showing the structure of the surface layer in the test piece obtained according to Example 1-1.

FIG. 7 is a photograph with a magnification of 400 times showing the structure of the surface layer in the test piece obtained according to Example 1-2.

FIG. 8 is a photograph with a magnification of 400 times showing the structure of the surface layer portion of the test piece obtained in Example 1-3.

FIG. 9 is a photograph with a magnification of 400 times showing the structure of the surface layer portion of the test piece obtained in Example 1-4.

FIG. 10 shows the structure of the surface layer in the test piece obtained by the comparative example in Example 1, and has an enlargement ratio of 40.
It is a photograph of 0 times.

FIG. 11 is a flowchart showing a manufacturing process of a normal plating cylinder.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 workpiece 2 blast material particles 3 ceramic particles 4 modified layer 10 unevenness 10 a convex portion 10 b concave portion 11 roller 12 oil sump 20 cylinder block 21 bore inner surface 22 head surface 30 blast device 31 blast gun 32 injection hole

Claims (6)

[Claims] 1. A modified layer in which ceramic particles are dispersed and fixed on a surface layer of an aluminum alloy member by spraying ceramic particles and colliding the surface with the surface of the aluminum alloy member. Surface treatment method for an aluminum alloy member. Forming a modified layer in which the ceramic particles are dispersed and fixed on the surface layer of the aluminum alloy member by spraying the ceramic particles and colliding the surface with the surface of the aluminum alloy member; Subjecting the irregularities formed on the surface of the modified layer to a surface finish by rolling. 3. The method for treating a surface of an aluminum alloy member according to claim 1, wherein glass particles having a non-angular shape are used as the ceramic particles. 4. An aluminum alloy member which has been subjected to a surface treatment by the method according to claim 1. 5. A modified layer in which the ceramic particles are dispersed and fixed on the surface of the inner surface of the bore by spraying and colliding the ceramic particles with the inner surface of the bore of the cylinder block made of an aluminum alloy. And a step of subjecting the unevenness formed on the surface of the modified layer to a surface finish by rolling. 6. A modified layer in which the ceramic particles are dispersed and fixed on the surface of the inner surface of the bore by spraying and colliding the ceramic particles with the inner surface of the bore of the cylinder block made of an aluminum alloy. A surface treatment of a surface layer of the inner surface of the bore by a surface treatment method including a step of performing a surface finish by rolling on the surface of the modified layer.