CN108642417A

CN108642417A - A kind of Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes

Info

Publication number: CN108642417A
Application number: CN201810515449.XA
Authority: CN
Inventors: 吴远志; 李庆芬; 刘伟; 邓彬; 叶拓; 周小桃
Original assignee: Hunan Institute of Technology
Current assignee: Hunan Institute of Technology
Priority date: 2018-05-25
Filing date: 2018-05-25
Publication date: 2018-10-12

Abstract

A kind of Ultra-fine Grained Mg 3Al 1Zn alloy short flow processes, the casting mould of casting including alloy and hot-working, alloy is rectangular water cooled copper mould, and mold compact dimensions are 150mm*150mm*150mm, mold cooling water capacity is 300 ± 10ml, and cooling water flow velocity is 3 ± 0.5 liters/min；The hot processing temperature of alloy is 250 ± 5 DEG C, the hot-working preincubation time is 10 ± 1 minutes, thermal processing method is that small passage strains the forging of three axis of high strain rate, forging equipment is pneumatic hammer, not Repeat-heating between passage, passage dependent variable is 10 ± 0.5%, and rolling pass is 12 passages, and the type of cooling is air-cooled.The present invention prepares the cast sturcture of uniform isometric and approximate solid solution by water cooled copper mould；A large amount of twins, by twin crystal induction dynamic recrystallization, rapid refining alloy tissue are generated using high-speed deformation；Suitable for preparing Ultra-fine Grained Mg 3Al 1Zn alloy block materials.

Description

A kind of Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes

Technical field

The present invention relates to a kind of Mg-3Al-1Zn alloy preparation methods, and in particular to a kind of Ultra-fine Grained Mg-3Al-1Zn alloys Short flow process.

Background technology

Magnesium alloy is most light structural metallic materials, has high specific strength, high specific stiffness, good damping capacity, excellent Thermal conductivity and electric conductivity, good dimensional stability, electromagnetic wave shielding and the characteristics such as be easily recycled.In recent years, with the energy With becoming increasingly conspicuous for environmental problem, magnesium alloy emerges rapidly as new engineering material, is increasingly becoming aluminium alloy, steel and engineering The ideal substitute of the engineering material such as plastics has weight in fields such as aerospace, communications and transportation, weaponry and electronic apparatus The application value and wide application prospect wanted.

But the lag of low strength and the high-strength magnesium alloy exploitation of magnesium alloy seriously constrains the extensive of magnesium alloy and answers With therefore, the research and development of high-strength magnesium alloy meets the important development direction of industrial requirement as it.Research shows that crystal grain is thin Change is to prepare the effective ways of high-strength and high ductility material, and large plastometric set technique is because its strong grain refining capability is in magnesium in recent years It is widely used in alloy, main method includes Equal Channel Angular Pressing, high pressure torsion, reciprocating extrusion, accumulation ply rolling etc..But Existing method operating process is complicated, is unsuitable for industrialized production, and is unsuitable for processing blocks of large material.

Invention content

The technical problem to be solved by the invention is to provide a kind of Ultra-fine Grained Mg-3Al-1Zn alloy short routes preparation sides Method, this method is simple for process, high in machining efficiency, is suitable for block materials and processes.

The technical solution adopted by the present invention to solve the technical problems is：A kind of Ultra-fine Grained Mg-3Al-1Zn alloy short routes Preparation method includes the casting and hot-working of alloy, and the casting mould of the alloy is rectangular water cooled copper mould, mold compact dimensions For 150mm*150mm*150mm, mold cooling water capacity is 300 ± 10ml, and cooling water flow velocity is 3 ± 0.5 liters/min；It is described The hot processing temperature of alloy is 250 ± 5 DEG C, and the hot-working preincubation time is 10 ± 1 minutes, and thermal processing method strains for small passage Three axis of high strain rate forges, and forging equipment is pneumatic hammer, and Repeat-heating, passage dependent variable are not 10 ± 0.5% between passage, are become Shape passage is 12 passages, and the type of cooling is air-cooled.

Further, the rectangular water cooled copper mould mold cooling water capacity is 300 ± 5ml, more preferable 300ml.

Further, the rectangular water cooled copper mould cooling water flow velocity is 3 ± 0.2 liters/min, more preferable 3 liters/min.

Further, the state before the alloy hot-working is as cast condition block materials.

Further, the hot processing temperature of the alloy is 250 ± 2 DEG C, more preferable 250 DEG C.

Further, the hot-working preincubation time is 10 ± 0.5 minutes, more preferable 10 minutes.

Further, passage dependent variable is 10 ± 0.2%, more preferable 10%.

The beneficial effects of the present invention are：

(1) casting mould of alloy is rectangular water cooled copper mould, and mold compact dimensions are 150mm*150mm*150mm, mold Cooling water capacity is 300 ± 10ml, and cooling water flow velocity is 3 ± 0.5 liters/min, and ingot casting can obtain more uniform etc. at this time Axialite tissue, and alloying element has little time to be precipitated during being quickly cooled down, and single phase solid solution is obtained substantially, before hot-working Without being heat-treated.

(2) hot processing temperature of alloy is 250 ± 5 DEG C, and the processing preincubation time is 10 ± 1 minutes, is become at this temperature Shape can start basal slip, Prismatic slip and conical surface sliding simultaneously, while ensure material in the case where crystal grain does not occur and grows up Expect that core is consistent with surface temperature, ensures being smoothed out for post forming.

(3) thermal processing method is that small passage strains the forging of three axis of high strain rate, and forging equipment is pneumatic hammer, between passage not Repeat-heating, passage dependent variable are 10 ± 0.5%；Under the conditions of high-speed deformation, since the time that can be used for dislocation movement by slip is shorter, It is twin to become plastic deformation main mechanism, a large amount of twin is generated, by twin crystal induction dynamic recrystallization, rapid refining alloy group It knits；Promote the formation for intersecting twin by three directional loads ringing, twin density is improved, to ensure grain refining capability； Using 10 ± 0.5% small passage dependent variable, it is ensured that alloy will not form strong basal plane texture after forging, be conducive to improve The continuous deformation ability of alloy；In addition, being forged using pneumatic hammer, the temperature-rise effect of high-speed deformation can also be utilized to make up scattered The temperature that thermal conductivity causes declines, and saves heating process between passage, shortens the process-cycle.

Description of the drawings

Fig. 1 is the microstructure morphology of 1 casting alloy of embodiment；

Fig. 2 is that small passage strains three axis forging technology schematic diagram of high strain rate；

Fig. 3 is the microstructure morphology of the 2nd passage alloy in 1 forming process of embodiment；

Fig. 4 is the microstructure morphology of the 4th passage alloy in 1 forming process of embodiment；

Fig. 5 is the microstructure morphology of the 8th passage alloy in 1 forming process of embodiment；

Fig. 6 is the microstructure morphology of the 10th passage alloy in 1 forming process of embodiment；

Fig. 7 is the microstructure morphology of the 12nd passage alloy in 1 forming process of embodiment.

Specific implementation mode

The invention will be further described with reference to the accompanying drawings and embodiments.

Embodiment 1

The present embodiment selected materials are Mg-3Al-1Zn, and sample length, width and height are respectively 35mm, 35mm, 40mm before hot-working.

A kind of Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes, include the following steps：

1) casting technique：Mg-3Al-1Zn alloy melts are prepared according to magnesium alloy smelting method, by the slow side of pouring into of melt Shape water cooled copper mould, copper mold compact dimensions are 150mm*150mm*150mm, and mold cooling water capacity is 300ml, and cooling water flow velocity is 3 liters/min, casting process prevents from burning by spreading Cosan, takes out ingot casting after cooling；Under the action of water cooled copper mould, close Golden solidified structure is more uniform equiax crystal, and crystal boundary nearby not coarse the second phase, obtains single phase solid solution substantially Tissue, as shown in Figure 1；

2) hot-working heating process：Sample is placed in heating furnace before forming and carries out heating and thermal insulation, heating temperature is set It is set to 250 DEG C, soaking time is 10 minutes, so that sample is heated evenly, ensures material cores in the case where crystal grain does not occur and grows up Portion is consistent with surface temperature；

3) small passage strain three axis of high strain rate forging：Heat processing and forming carries out on pneumatic hammer, and pneumatic hammer forges Number is 200 times/min, and rapidity of blow 5m/s is shaped using primary heating, i.e., forges work without heating, three axis between passage Skill is as shown in Fig. 2, forge face by A-B-C-A ..., and sequence carries out, and often forges a face and is counted as a time, pass deformation 10%, Sample is carried out after the completion of hot-working air-cooled to retain high temperature deformation tissue.

Sample surfaces are good after hot-working, without apparent crackle, are lost without apparent macroscopic view.

1. microstructure characterizes：It chooses sample core in embodiment 1 and prepares microstructure observation's sample, by edge sample, in advance Mill, polishing, corrosion, using the sample after the micro- sem observation corrosion of MM6 type horizontal metallurgicals, the plane of observation is forged before sampling Direction, displaing micro tissue topography is respectively as shown in Fig. 3-Fig. 7.

It can be seen that in embodiment 1 from Fig. 3-Fig. 7, deform early period, generate in initial grain a large amount of interlaced twin Crystalline substance, while having a small amount of recrystal grain on twin, as shown in Figure 3；With the continuation of deformation, the recrystallization degree on twin It increases rapidly, while continuing to generate a large amount of twin in no region recrystallized, as shown in Figure 4-Figure 6；When deform into When row is to 12 passage, alloy realizes perfect recrystallization, and average grain size is 5 μm, as shown in Figure 7.

Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes of the present invention, are quickly cooled down by water cooled copper mould, The cast sturcture for obtaining uniform isometric and approximate solid solution, without heat treatment before ingot casting hot-working；It is generated using high-speed deformation big Twin is measured, and passes through twin crystal induction dynamic recrystallization, rapid refining alloy tissue；Promote to intersect by three directional loads ringing The formation of twin improves twin density, to ensure grain refining capability；It is made up simultaneously by the temperature-rise effect of high-speed deformation scattered The temperature that thermal conductivity causes declines, need not heating between passage.Process-cycle of the invention is short, suitable for preparing Ultra-fine Grained Mg-3Al-1Zn deformations Magnesium alloy block materials.

Finally it is pointed out that above example is only intended to illustrate rather than limitation, in fact, of the invention Method other alloys are equally applicable；When those skilled in the art do simple replacement to product under the teachings of the present invention, Still fall within protection scope of the present invention.

Claims

1. a kind of Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes, it is characterised in that：Casting and heat including alloy add The casting mould of work, the alloy is rectangular water cooled copper mould, and mold compact dimensions are 150mm*150mm*150mm, mold cooling Water capacity is 300 ± 10ml, and cooling water flow velocity is 3 ± 0.5 liters/min；The hot processing temperature of the alloy is 250 ± 5 DEG C, heat It is 10 ± 1 minutes to process the preincubation time, and thermal processing method is that small passage strains the forging of three axis of high strain rate, and forging equipment is Pneumatic hammer, Repeat-heating, passage dependent variable are not 10 ± 0.5% between passage, and rolling pass is 12 passages, and the type of cooling is sky It is cold.

2. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1, it is characterised in that：The side Shape water cooled copper mould mold cooling water capacity is 300 ± 5ml.

3. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 2, it is characterised in that：The side Shape water cooled copper mould mold cooling water capacity is 300ml.

4. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, it is characterised in that： The rectangular water cooled copper mould cooling water flow velocity is 3 ± 0.2 liters/min.

5. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 4, it is characterised in that：The side It is 3 liters/min that shape water cooled copper mould, which cools down water flow velocity,.

6. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, it is characterised in that： State before the alloy hot-working is as cast condition block materials.

7. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, it is characterised in that： The hot processing temperature of the alloy is 250 ± 2 DEG C.

8. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, it is characterised in that： The hot-working preincubation time is 10 ± 0.5 minutes.

9. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, it is characterised in that： Passage dependent variable is 10 ± 0.2%.

10. Ultra-fine Grained Mg-3Al-1Zn alloy short flow processes according to claim 1 or 2 or 3, feature exist In：Passage dependent variable is 10%.