Prepare the method for ultra-fine crystal magnesium manganese alloy
Technical field
The invention belongs to field of magnesium alloy, relate to a kind of ultra-fine crystal magnesium Zn-Al hydrotalcite magnesium alloy, particularly a kind of method being prepared ultra-fine crystal magnesium manganese alloy by thermal treatment and crimp.
Background technology
Magnesium alloy excellent combination property, is specially adapted to light structures part, but the low and feature that is plastic deformation ability of magnesium alloy self-strength limits its range of application as structured material.For improving intensity and the plastic deformation ability of magnesium alloy, the following two kinds of methods of normal employing:
One, optimized alloy composition:
Usually in magnesium alloy, a certain amount of zirconium is added, using zirconium as the grain-refining agent of magnesium alloy, can the as-cast structure of Refining Mg Alloy significantly, and then improve the mechanical property of magnesium alloy.But zr element is expensive, and easy scaling loss in fusion process, hinder the application containing zirconium magnesium alloy; Usage quantity at present containing zirconium magnesium alloy is less than 1% of the total consumption of magnesium alloy, is mainly used in the special dimension such as aerospace and military affairs.
Two, deformation processing is carried out to magnesium alloy:
Extruding, rolling or conducting forging processing can significantly improve the intensity of magnesium alloy, but deformation processing can be fallen low-alloyed moulding usually.
Magnesium-zincium-manganese based magnesium alloy is a kind of novel wrought magnesium alloys not containing your element zirconium developed in recent years, after two-stage time effect thermal treatment process, its intensity can reach with containing the suitable strength level of zirconium magnesium alloy, but its unit elongation comparatively As-extruded significantly reduce, also far below containing zirconium magnesium alloy.
Refined crystalline strengthening is uniquely a kind of schedule of reinforcement that simultaneously can improve wrought magnesium alloys intensity and plasticity known at present, therefore, by preparing thin grained magnesium alloy thus improving the plasticity of magnesium alloy and intensity has very important significance.
Summary of the invention
In view of this, the object of the present invention is to provide a kind of method preparing ultra-fine crystal magnesium manganese alloy.
For achieving the above object, the invention provides following technical scheme:
Prepare the method for ultra-fine crystal magnesium manganese alloy, it is characterized in that, comprise the following steps:
1), solution treatment: by magnesium alloy 380 DEG C ~ 440 DEG C insulations 12 ~ 20 hours, be cooled to room temperature;
2), ageing treatment: by step 1) process after magnesium alloy be heated to 200 DEG C ~ 250 DEG C, be incubated 20 ~ 48 hours, be cooled to room temperature;
3), extrusion process: by step 2) process after magnesium alloy carry out extrusion process at 270 DEG C ~ 310 DEG C.
Prepare the preferred of ultra-fine crystal magnesium manganese alloy method as the present invention, during solution treatment, temperature is 400 DEG C ~ 420 DEG C, and soaking time is 14 ~ 18 hours; During ageing treatment, temperature is 220 ~ 240 DEG C, and soaking time is 25 ~ 40 hours; During extruding, temperature is 280 ~ 300 DEG C.
Prepare the preferred of ultra-fine crystal magnesium manganese alloy method as the present invention, described magnesium alloy chemical composition is: Zn:5.0 ~ 6.5%wt; Mn:0.8 ~ 1.5%wt; Inevitable impurity≤0.15%wt; Surplus is magnesium.
Prepare the preferred of ultra-fine crystal magnesium manganese alloy method as the present invention, during extrusion process, extrusion ratio is 10-60, extrusion speed 1 ~ 10 mm/second.
Prepare the preferred of ultra-fine crystal magnesium manganese alloy method as the present invention, during extrusion process, extrusion ratio is 20-30, extrusion speed 2 ~ 5 mm/second.
Prepare the preferred of ultra-fine crystal magnesium manganese alloy method as the present invention, during solution treatment, adopt the mode of water-cooled to be cooled to room temperature, during ageing treatment, adopt the mode of air cooling to be cooled to room temperature.
Beneficial effect of the present invention is:
The present invention prepares the method for ultra-fine crystal magnesium manganese alloy, first as-cast magnesium alloy is placed in 380 DEG C ~ 440 DEG C insulations 12 ~ 20 hours, segregation now in ingot casting is eliminated, and the zinc overwhelming majority simultaneously in alloy all solid solution enters in matrix, after warm water quench, obtain super saturated solid solution; Then by magnesium alloy heat to 200 DEG C ~ 250 DEG C, be incubated 20 ~ 48 hours, the overaging that the generation now in alloy is serious, Zn element is almost all with MgZn
2form exist; Finally, the magnesium alloy after 270 DEG C ~ 310 DEG C extrusion process timeliness, a large amount of MgZn that now overaging produces
2strengthening phase becomes the heterogeneous forming core core (MgZn in Dynamic Recrystallization in extrusion process
2having two kinds of patterns mutually, is the β with matrix coherence respectively
1and with the β of matrix half coherence
2, β
1and β
2be the crystalline structure of close-packed hexagonal, and the crystal parameters of lattice parameter and magnesium closely, for dynamic recrystallization provides heterogeneous nuclei); In addition, the MgZn of even dispersion distribution
2become the obstacle in Dynamic Recrystallization, effectively stop grain growth, the extruded Magnesium Alloy crystal grain finally obtained very tiny (being on average about 1 μm).
In addition, when the present invention prepares the method hot extrusion of ultra-fine crystal magnesium manganese alloy, extrusion temperature is not higher than 320 DEG C, and the strict extrusion speed controlled in extrusion process, prevent the heat produced in extrusion process from making MgZn
2decompose.
Further, adopt warm water quench when the present invention prepares the method solution treatment of ultra-fine crystal magnesium manganese alloy, can prevent ingot casting from ftracture, improve solid solubility, thus during increase ageing treatment separate out the content of second-phase.
Accompanying drawing explanation
In order to make object of the present invention, technical scheme and beneficial effect clearly, the invention provides following accompanying drawing and being described:
Fig. 1 be embodiment and comparative example's gained magnesium alloy sample extension time engineering stress strain curve;
Fig. 2 is the microtexture metallograph of embodiment 1 gained magnesium alloy;
Fig. 3 is the microtexture scanned photograph of embodiment 1 gained magnesium alloy;
Fig. 4 is the metallograph of comparative example 1 gained magnesium alloy.
Embodiment
Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described in detail.
Embodiment 1:
The present embodiment prepares the method for ultra-fine crystal magnesium manganese alloy, comprises the following steps:
1), melting: adopt high purity magnesium, analytical pure zinc, Mg-4Mn master alloy carries out melting at vacuum induction melting furnace, use cast-iron pot, fusion process is logical argon shield all the time, after metal dissolves completely, induction stirring 5-10 minute, then slowly shrend cooling;
2), machining: the size according to extrusion machine container carries out sawing, and railway carriage etc. are machined into suitable dimension;
3), solution treatment: by magnesium alloy 420 DEG C of insulations 12 hours, heat up 6 ~ 8 hours with stove, hot water (hot water temperature is 60-70 DEG C) is quenched to room temperature subsequently;
4), ageing treatment: by step 1) process after magnesium alloy be heated to 230 DEG C, be incubated 24 hours, air cooling is to room temperature;
5), extrusion process: by step 2) process after magnesium alloy 300 DEG C insulation 1 hour after carry out extrusion process, during extruding control extrusion ratio 25, extrusion speed 2 ~ 5 mm/second.
In the present embodiment, the chemical composition of obtained magnesium alloy is: Zn:5.85%wt; Mn:0.9%wt; Inevitable impurity≤0.15%wt; Surplus is magnesium.
Embodiment 2:
The difference of method and embodiment 1 that the present embodiment prepares ultra-fine crystal magnesium manganese alloy is:
During the present embodiment ageing treatment, magnesium alloy is heated to 230 DEG C, be incubated 48 hours, air cooling is to room temperature.
Comparative example 1:
The difference of this comparative example and embodiment 1 is: this comparative example is directly to step 3) magnesium alloy after solution treatment extrudes at 300 DEG C.
Comparative example 2:
This comparative example prepares the method for magnesium alloy, comprises the following steps:
1), melting: adopt high purity magnesium, analytical pure zinc, Mg-4Mn master alloy carries out melting at vacuum induction melting furnace, use cast-iron pot, fusion process is logical argon shield all the time, after metal dissolves completely, induction stirring 5-10 minute, then slowly shrend cooling;
2), machining: the size according to extrusion machine container carries out sawing, and railway carriage etc. are machined into suitable dimension;
3), Homogenization Treatments: alloy was 330 DEG C of homogenizing 24 hours, and air cooling is to room temperature;
4), extrusion process: by step 3) process after magnesium alloy 350 DEG C insulation after carry out extrusion process;
5), solution treatment: by step 4) gained magnesium alloy be heated to 420 DEG C insulation 2h, cold quenching.
Comparative example 3:
This comparative example prepares the method for magnesium alloy, comprises the following steps:
1), melting: adopt high purity magnesium, analytical pure zinc, Mg-4Mn master alloy carries out melting at vacuum induction melting furnace, use cast-iron pot, fusion process is logical argon shield all the time, after metal dissolves completely, induction stirring 5-10 minute, then slowly shrend cooling;
2), machining: the size according to extrusion machine container carries out sawing, and railway carriage etc. are machined into suitable dimension;
3), Homogenization Treatments: alloy was 330 DEG C of homogenizing 24 hours, and air cooling is to room temperature;
4), extrusion process: by step 3) process after magnesium alloy 350 DEG C insulation after carry out extrusion process;
5), solution treatment: by step 4) gained magnesium alloy be heated to 420 DEG C insulation 2h, cold quenching.
6), ageing treatment: by step 5) gained magnesium alloy is heated to 180 DEG C of timeliness 16h and obtains product.
Comparative example 4:
The difference of the present embodiment and comparative example 3 is, the present embodiment ageing treatment is carried out in two steps:
First by step 5) solution treatment gained magnesium alloy is heated to 90 DEG C of preageing 24h, then by this magnesium alloy 180 DEG C of timeliness 16h.
Performance test:
1, mechanics properties testing:
According to the standard of GB GB228-2002, embodiment 1,2 and comparative example 1-4 process gained magnesium alloy materials are processed into standard tensile specimen and carry out tension test, as shown in Figure 1, it is as shown in table 1 that analysis chart 1 obtains each embodiment magnesium alloy main mechanical index to gained stress strain curve:
Table 1 embodiment and the test of comparative example's gained Properties of Magnesium Alloy
Embodiment |
Thermal treatment process |
Yield strength (MPa) |
Tensile strength (MPa) |
Unit elongation (%) |
Embodiment 1 |
Solid solution+timeliness+extruding |
278 |
343 |
17.2 |
Embodiment 2 |
Solid solution+timeliness+extruding |
271 |
341 |
19.1 |
Comparative example 1 |
As-extruded |
205 |
310 |
12.3 |
Comparative example 2 |
Extruding+solid solution |
192 |
297 |
11.6 |
Comparative example 3 |
Extruding+solid solution+timeliness |
281 |
333 |
7.8 |
Comparative example 4 |
Extruding+solid solution+timeliness I+ timeliness II |
340 |
361 |
6.3 |
As can be seen from Fig. 1 and table 1, compared with the magnesium alloy after embodiment 1,2 adopts the inventive method process extrudes merely gained magnesium alloy with comparative example 1, every mechanical property equal be improved significantly; Compared with comparative example 3 single-stage aging gained magnesium alloy, intensity is more or less the same, but moulding increase nearly 150%; Compared with comparative example 4, although tensile strength slightly declines, mouldingly add 200% nearly.
Therefore, the present invention prepares the method for ultra-fine crystal magnesium manganese alloy, can put forward heavy alloyed intensity and moulding simultaneously, and compared with the method for the two-stage time effect of comparative example 4, also have with short production cycle, the advantage that efficiency is high.
2, microstructure analysis:
Fig. 2 is the microtexture metallograph of embodiment 1 gained magnesium alloy; Fig. 3 is the microtexture scanned photograph of embodiment 1 gained magnesium alloy; Fig. 4 is the metallograph of comparative example 1 gained magnesium-zinc-manganese alloy.
Comparison diagram 2, Fig. 4 can find out, the Magnesium Alloy after embodiment 1 adopts the inventive method process obtains obvious refinement, and the fine microstructures of alloy is even; What in Fig. 3, contrast was brighter is magnesium zinc second-phase, as can be seen from the figure, the distribution fine uniform disperse of second-phase, and intra-die and crystal boundary all exist; This illustrates that the second-phase of this Dispersed precipitate not only plays the effect of crystal grain thinning, makes the motion of obstruction dislocation at alloy stress deformation, puies forward heavy alloyed intensity.
In sum, the present invention adds the magnesium-zinc-manganese wrought magnesium alloys of extrusion process process through overaging, and its mechanical property improves greatly compared with traditional technology, has mating of extraordinary intensity and plasticity; Every mechanical property of alloy all meets or exceeds commercial containing zirconium magnesium alloy (as ZK60), effectively expand the use range of magnesium-manganese-manganese series magnesium alloy, can substitute further containing zirconium magnesium alloy materials, be applied to the fields such as aerospace, military affairs, industry.
It should be noted that, although only disclose chemical composition in embodiment for " Zn:5.85%wt; Mn:0.9%wt; Inevitable impurity≤0.15%wt; Surplus is magnesium " magnesium alloy; but according to the understanding of those skilled in the art; technical scheme disclosed in this invention is not only applicable to the magnesium alloy of this composition, is also applicable to all Mg-Zn-Mn series magnesium alloys, and can further genralrlization to all Mg-Zn series magnesium alloys.
What finally illustrate is, above preferred embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although by above preferred embodiment to invention has been detailed description, but those skilled in the art are to be understood that, various change can be made to it in the form and details, and not depart from claims of the present invention limited range.