CN101307419B

CN101307419B - Grain refining method of aluminium bronze

Info

Publication number: CN101307419B
Application number: CN2008100550241A
Authority: CN
Inventors: 张瑞军; 刘建华
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2008-05-29
Filing date: 2008-05-29
Publication date: 2010-06-23
Anticipated expiration: 2028-05-29
Also published as: CN101307419A

Abstract

The invention discloses a method for thinning aluminium bronze crystal grains. The invention is characterized in that: the method comprises two parts of high pressure treatment and heat treatment, wherein, in the high pressure treatment, aluminium bronze is treated in a solid-state phase change region; the high pressure treatment comprises the following process parameters that: the pressure is between 1 and 6 GPa; the treatment temperature is between 700 and 900 DEG C and the heat preservation time is between 5 and 20 minutes; and the aluminium bronze is naturally cooled to the room temperature through power cutoff and pressure maintenance; in the heat treatment: the treatment temperature is between 600 and 750 DEG C; the heat preservation time is between 0.5 and 2 minutes; and the cooling speed is between 5 and 30 DEG C/min; and the aluminium bronze is cooled to the room temperature. The Al content in the aluminium bronze is between 10 and 15 weight percent. In the method, the aluminium bronze can acquire thinner and evener crystal grains by a combination of high pressure treatment and heat treatment, thereby achieving the perfect effect of crystal grain thinning.

Description

A kind of method of McGill metals grain refining

Technical field

The invention belongs to metal material field, relate to a kind of processing method that is used for refinement McGill metals tissue.

Background technology

McGill metals has excellent mechanical property, wear resistance, solidity to corrosion and oxidation-resistance, in machinery, instrument, has obtained in the fields such as automobile, boats and ships and ocean using widely.Along with the develop rapidly of modern industry, every field is all had higher requirement for the xantal material.Crystal grain thinning can improve many-sided use properties of this alloy simultaneously.At present, the method of crystal grain thinning has following several: (1) adds alloying element: adopt this method to be easy to apply industrial, but can cause material cost to improve, for heat treating regime especially temperature strict requirement is arranged, otherwise in heat treatment process subsequently, can cause grain growth.In addition, because the adding of alloying element will be introduced impurity element, in process of setting, for various reasons, cause the even segregation phenomena of chemical composition and tissue odds, even form nonmetal inclusion.(2) rapid solidification method: the advantage of this method is can directly obtain finished product without pilot process behind the alloy melting, good in refining effect, but it has reduced the degree of order of copper alloy, transformation temperature instability when timeliness, on size and dimension, also there is limitation, can only obtains thin ribbon shaped, thread product.(3) powder metallurgic method: the copper-based memory alloy of this method preparation has anti-loop attenuation and good ductility, but its processing parameter is difficult to control.(4) thermomechanical treatment: form a large amount of tiny new equi-axed crystal, this method makes the crystallization degree of order of alloy reduce.(5) electro-pulse modification is handled: have effective thinning effect, and the equipment of this technology and technology are all simple, easy and simple to handle, but obvious inadequately for the thinning effect of the goods of larger cross-section, only rest on the experimental phase.

Summary of the invention

The technical problem to be solved in the present invention is the deficiency that exists at existing McGill metals crystal grain thinning method, and a kind of McGill metals crystal grain thinning method is provided, and this invented technology is simple, cost is low and reliable quality.

The technical solution adopted for the present invention to solve the technical problems is that the concrete steps of described method are as follows:

1. high-pressure treatment process: its concrete processing parameter is: pressure is 1～6GPa, and Heating temperature is 700～900 ℃, and soaking time is 5～20min, and the outage pressurize naturally cools to room temperature.

2. thermal treatment process: heat treatment process parameter is: Heating temperature is 600～750 ℃, and soaking time is 0.5～2min, and speed of cooling is that 2～30 ℃/min is cooled to room temperature.

The McGill metals that adopts this method to handle can obtain the tiny weave construction of uniform crystal particles.

At first the McGill metals sample of having smelted is carried out phase transition under high pressure and handle, the purpose of autoclaving is in order to destroy thick original structure, for subsequently operation creates conditions.In the autoclaving process, hyperpressure can increase defectives such as the inner distortion of alloy structure, and this formation for new nucleus provides favourable position, and hyperpressure also can make the required critical free energy of formation nucleus reduce simultaneously, causes the nucleation rate of new crystal grain to improve.Moreover, the diffusion of atom is difficult under the too high pressure, suppressed growing up of nucleus, so the grain-size that obtains behind McGill metals generation phase transformation under the high pressure effect is little, but defectives such as crystal boundary density and distortion are more, uneven components increase in the tissue simultaneously, these will provide favourable position for the forming core of xantal nucleus in heat treatment process subsequently, be beneficial to form tiny nucleus.For guaranteeing this alloy realization high-voltage solid-state phase transformation, whole technological process is carried out under the high pressure effect.

Again the McGill metals sample after the autoclaving is heat-treated subsequently, heat treated purpose is to make McGill metals that phase transformation take place again, on the one hand, can fully eliminate the tissue defects that autoclaving is brought, on the other hand, can obtain thinner tissue by the phase transformation McGill metals.Heat treated Heating temperature should be a little more than transformation temperature (about 563 ℃), soaking time is short, controls its speed of cooling, when alloy is undergone phase transition, the crystal grain that forms can Yin Wendu too high and time long and grow up, make grain-size and form obtain controlling preferably.

The invention has the beneficial effects as follows: the inventive method is simple, and technology is easy to control, and adopts this processing method, and what can make the McGill metals acquisition organizes uniform crystal particles tiny, and steady quality is reliable, is suitable for industrial application.Simultaneously, this method can be eliminated pore, trachoma and casting flaw such as loose, and has improved the degree of compactness of alloy, has strengthened over-all propertieies such as the intensity of McGill metals and wear resistance.

Description of drawings

Fig. 1 is a casting al-bronze alloy metallographic structure photo;

Fig. 2 is the McGill metals metallographic structure photo after handling with embodiment 1;

Fig. 3 is the McGill metals metallographic structure photo after handling with embodiment 2;

Fig. 4 is the McGill metals metallographic structure photo after handling with embodiment 3.

Embodiment:

Below by specific embodiment technical scheme of the present invention is further described.

Embodiment 1

According to crystal fining method of the present invention, a kind of McGill metals has been carried out the grain refining processing, its chemical ingredients (massfraction wt%) is, and Cu 88.26%, and Al 11.54%, and Bi 0.14%, all the other 0.06% impurity.With oxygen free copper (purity 99.99%), aluminium powder (purity 99.7%) and bismuth meal (purity 99.9%) is raw material, melting in the 2Kg vacuum induction furnace, when being 1200～1250 ℃, temperature comes out of the stove ф 50 * 100mm ingot casting in graphite mo(u)ld, being cast into when temperature is reduced to 1150～1180 ℃.

The McGill metals sample of gained is tested at the enterprising horizontal high voltage of CS-IIB type six-plane piercer.Employing pressure is 6GPa, Heating temperature is 700 ℃, soaking time is 5min, the outage pressurize is cooled to room temperature (about 25 ℃), then the sample after the autoclaving is heat-treated in the STA449C thermal analyzer, Heating temperature is 650 ℃, soaking time 1min, and speed of cooling is that 5 ℃/min is cooled to room temperature.Find through the metallography microscope sem observation, α phase crystal grain is thick and inhomogeneous in the preceding McGill metals tissue of processing, some is thick en plaque, using the α that this technology obtains exists with particulate state and fine strip shape, it is evenly tiny that crystal grain becomes, its grain-size is about 15～20 μ m, and its grain-size is to handle 1/5～1/10 of preceding McGill metals grain-size.

Embodiment 2

The composition of experiment material, preparation are identical with embodiment 1 with technological process, have only autoclaving parameter difference.Adopting pressure in the present embodiment is 1GPa, and Heating temperature is 900 ℃, and soaking time is 20min, and the outage pressurize is cooled to room temperature (about 25 ℃).Present embodiment has used lower pressure and higher temperature and soaking time.Find that through the metallography microscope sem observation thinning effect of McGill metals tissue is apparent in view, α phase grain-size is about 15～20 μ m, and is basic identical with embodiment one thinning effect.

Embodiment 3

The composition of experiment material, preparation are identical with embodiment 1 with technological process, have only the heat treatment parameter difference.Adopting Heating temperature in the present embodiment is 750 ℃, soaking time 0.5min, and speed of cooling is that 20 ℃/min is cooled to room temperature.Present embodiment has used higher temperature, short soaking time and speed of cooling faster.Find through the metallography microscope sem observation, the thinning effect of McGill metals tissue also relatively significantly, α phase grain-size is about 12～18 μ m, its grain-size is to handle 1/6～1/12 of preceding McGill metals grain-size, only handling the back McGill metals, to organize acicular α to compare among the embodiment 1 many, and granular α compares lacking among the embodiment 1.

Claims

1. the method for a McGill metals grain refining, it is characterized in that: described method is made up of autoclaving and thermal treatment two portions, and the McGill metals that adopts this method to handle can obtain the tiny weave construction of uniform crystal particles;

High-pressure treatment process is: carry out in the solid-state phase changes district, its processing parameter is: pressure is 1～6GPa, and treatment temp is 700～900 ℃, and soaking time is 5～20min, and the outage pressurize naturally cools to room temperature;

The xantal sample after the autoclaving is heat-treated subsequently, thermal treatment process is again: treatment temp is 600～750 ℃, and soaking time is 0.5～2min, and speed of cooling is that 5～30 ℃/min is cooled to room temperature.

2. the method for McGill metals grain refining according to claim 1 is characterized in that: the content wt% of Al is 10～15% in the McGill metals.