Biomedical Mg-Sn-Zn-Mn magnesium alloy and preparation method thereof
Technical field
What the present invention relates to is a kind of alloy, the present invention also relates to a kind of preparation method of alloy.Particularly a kind of Alloy And Preparation Method for biomedical materials field.
Background technology
Current degradable biological medical material mostly is the macromolecular material such as poly(lactic acid) (PLA), polyglycolic acid (PGA), but it exists, and mechanical property is on the low side, processing difficulties, vivo degradation product easily cause the problem such as inflammation and swelling.Degradable magnesium alloy has good comprehensive mechanical property and machining property, such as, extrude AZ31 magnesium alloy and have higher intensity, can meet the requirement of bio-medical material to mechanical property.And the Young's modulus of magnesium alloy is about 40GPa, with osseous tissue closely, effectively can alleviate " stress shielding " effect.Magnesium ion (Mg in degraded product
2+) be the second important positively charged ion in human body cell.Magnesium also has multiple special physiological function, and it can swash in vivo multiple enzyme, suppresses dysautonomia excitability, maintains the stability of nucleic acid construct, participates in the synthesis of body internal protein, Muscle contraction and thermoregulation.Magnesium also affects " passage " of the movement of potassium sodium calcium ion intraor extracellular, and has the effect maintaining microbial film current potential.But the standard potential of Mg-based hydrogen storage is lower (-2.36V SCE), not corrosion-resistant, especially containing Cl
-human body environment in corrosion degradation speed too fast.People develop medical corrosion-resisting type magnesium alloy for this reason, can consult that application number is 200610046470.7, name is called that " medical corrosion-resisting type magnesium alloy " and application number are 200710011008.8, name is called the technical scheme recorded in the patent document of " medical high-strength anticorrosion magnesium alloy ".
Another one restriction magnesium alloy widespread use be that under its room temperature and lesser temps (lower than 498K), plasticity is low, deformation processing difficulty.This is because magnesium belongs to the metal of Patterns for Close-Packed Hexagonal Crystal structure, under room temperature, independent slip-system is few, only has basal slip.For magnesium and the poor problem of Alloy At Room Temperature plasticity thereof, people develop high-obdurability magnesium alloy, can consult that application number is 200810234439.5, name is called " a kind of tough magnesium alloy and preparation method thereof "; Application number is 200910011280.5, name is called " a kind of stanniferous high-obdurability magnesium alloy with zinc and preparation method thereof "; Application number is 200910011283.9, name is called " a kind of stanniferous high-strength high-plasticity magnesium alloy with aluminium and preparation method thereof "; Application number is 200910067428.7, name is called " a kind of super-high-plasticity, cast Mg alloy with high strength and preparation method thereof ", application number is 200910067472.8, name is called that " a kind of high strength, high plastic magnesium alloy and preparation method thereof " and application number are 201010575745.2, name is called the technical scheme recorded in the patent document of " a kind of high plastic magnesium alloy and preparation method thereof ".
Mostly containing one or more in Al, Zn, Pb or rare earth in above-mentioned reference and other relevant magnesium alloy.As everyone knows, Al may cause some degenerative neurological diseases such as DE syndrome, senile dementia, is considered to a kind of low toxicity trace element of nonessential role; Data presentation in documents and materials, when Zn content is greater than 1%, hemolysis rate is often higher, is therefore not suitable for use in the biological implantation material directly contacted with blood; Plumbous (Pb) is that one has neurovirulent heavy metal element, and in vivo without any physiological function, its ideal concentration should be zero in blood; Although the rare earth element such as neodymium, yttrium can improve intensity and the solidity to corrosion of magnesium alloy, its biological effect is also indefinite at present, and therefore its security awaits long-term experimental observation.
In sum, urgently develop a kind of have concurrently nontoxic, can the new bio medical magnesium alloy system of the degradable and tough advantage of height, explore the possibility that it applies in stent and the Orthopeadic Surgery such as hone lamella, nail internal fixtion and embedded material.
Summary of the invention
The object of the present invention is to provide a kind of have concurrently nontoxic, can degradable and biomedical Mg-Sn-Zn-Mn magnesium alloy that height is tough.The present invention also aims to the preparation method that a kind of biomedical Mg-Sn-Zn-Mn magnesium alloy is provided.
The object of the present invention is achieved like this:
The each component of biomedical Mg-Sn-Zn-Mn magnesium alloy of the present invention and mass percent thereof are: Sn 1-5%, Zn 0.5-3%, Mn 0.15-1.5%, Impurity Fe < 0.005%, Cu < 0.002% and Ni < 0.002%, surplus is Mg.
Biomedical Mg-Sn-Zn-Mn magnesium alloy of the present invention selects each component and mass percent thereof to be further defined to: Sn2-4%, Zn 0.5-1.0%, Mn 0.15-1.0%, Impurity Fe < 0.002% or Fe/Mn < 0.02, Cu < 0.002% and Ni < 0.002%, surplus is Mg.
The preparation method of height of the present invention is tough biomedical Mg-Sn-Zn-Mn magnesium alloy comprises the following steps:
(1) according to mass percent be: Sn 1-5%, Zn 0.5-3%, Mn 0.15-1.5%, Impurity Fe < 0.005%, Cu < 0.002% and Ni < 0.002%, surplus is the ratio of Mg, adopts pure magnesium ingot, pure tin ingot, pure zinc ingot and Mg-Mn master alloy under flux protection, carry out melting, Mg-Sn-Zn-Mn series magnesium alloy ingot casting is made in casting;
(2) by Mg-Sn-Zn-Mn series magnesium alloy ingot casting at 300 DEG C-400 DEG C, be incubated after 3-5 hour and carry out extruding or rolling predeformation, deflection is less than 10%;
(3) the Mg-Sn-Zn-Mn series magnesium alloy after predeformation is carried out solution heat treatment, solid solution temperature is 400 DEG C-450 DEG C, and the solution treatment time is 12-28 hour, and the cold or air cooling of shrend, stove is to room temperature.
In magnesium alloy of the present invention, the effect of each element is as follows:
From the biological effect angle of tin, under normal circumstances, the toxicity of metallic tin is minimum, and animal per os takes in heavy dose of metallic tin, does not find specific toxicity.The grownup of a 70kg body weight about needs the tin of 7.0mg every day; From the mechanical property angle of magnesium alloy, tin can improve temperature-room type plasticity and the intensity of magnesium alloy.The mechanical properties of as cast condition and rolling state Mg-3Sn-1Mn alloy is respectively 184MPa and 207MPa, and unit elongation is respectively 24% and 26%.In addition, the compacting factor of metallic tin is 1.31, contributes to alloy surface and forms passive film, improve the solidity to corrosion of magnesium alloy.
From the biological effect angle of zinc, zinc participates in the formation of the zymophore of multiple mankind's important enzyme such as alkaline phosphatase, carbonic anhydrase, has the function of catalysis, structure and adjustment in metalloenzyme; Although zinc can not directly act on target-gene sequence, most zinc-binding protein can regulate the differentiation of cell, upgrade and participate in directly the regulation and control of genetic expression; Zinc can strengthen the immunologic function of human body, maintains the g and D of body; Experiment in vitro shows, zinc can maintain the barrier function of endothelial cellular membrane.From the mechanical property angle of magnesium alloy, zinc solid solubility is in the magnesium alloy 6.2%, magnesium alloy is had to the effect of solution strengthening.It is the very effective alloy element of another kind except aluminium.In addition, the local corrosion of magnesium alloy can be made when Zn content is below 2% to be inclined to and to diminish, thus effectively improve the corrosion resistance nature of magnesium alloy.
From the biological effect angle of manganese, manganese is to cardiovascular favourable element, especially to safeguarding that mitochondrial function is very important.And can bone growth and development be promoted, keep normal brain function, normal sugar, metabolism of fat can also be maintained, improve the hemopoietic function of body.Manganese can also strengthen endocrine function, maintains thyroid normal function, promotes the synthesis of sexual hormoue, regulates nerves reaction ability; Although manganese is little to the Effect on Mechanical Properties of magnesium alloy, even may reduce the plasticity of magnesium alloy a little, and manganese itself there is no benefit to the solidity to corrosion improving magnesium, excessive manganese is even also harmful to the corrosion of magnesium alloy.But manganese can suppress the disadvantageous effect of some impurity elements such as Fe, Cu and Ni widely, thus effectively improve the corrosion resistance nature of magnesium alloy.
The strengthening and toughening mechanism of of biomedical Mg-Sn-Zn-Mn magnesium alloy is twin crystal induction plastic mechanism.Mg-based hydrogen storage stacking fault energy is lower, and research shows, the stacking fault energy of material is lower more easily produces growth twin.Add the stacking fault energy that the alloy elements such as Sn, Zn and Mn reduce further alloy, make alloy " natural " in solution heat treatment process be easy to form raised growth twin; When the dislocation substructure formed in predeformation process is distributed in matrix equably, then may form very tiny twin.Matrix is cut into a lot of block by the appearance of a large amount of tiny twin, and its effect is similar to grain refining, dislocation motion resistance is increased, thus improves the intensity of magnesium alloy.Thus twin is more thin more, and the effect of its segmentation matrix is more remarkable, and reinforcing degree is also higher.
For magnesium and the alloy thereof of Patterns for Close-Packed Hexagonal Crystal structure, because under its room temperature, independent slip-system is few, twinly just to play a very important role in magnesium alloy plastic deformation.Twinly can adjust the orientation of crystal and discharge stress raisers, exciting further slippage, make slippage and twinly to hocket, thus larger deflection can be obtained, improving the unit elongation of magnesium alloy.
The invention has the beneficial effects as follows:
1. of the present invention a kind of have concurrently nontoxic, can degradable and biomedical Mg-Sn-Zn-Mn magnesium alloy that height is tough and preparation method thereof, adopt nontoxic Composition Design, alloy element tin, zinc and manganese are wherein all micro elements needed by human.
2. Mg-Sn-Zn-Mn series magnesium alloy of the present invention, employing multicomponent microalloying designs, play the interaction between each element self and each element, effectively reduced the stacking fault energy of this alloy, thus made its in solution heat treatment process " natural " be easy to form raised growth twin.
3. carry out the predeformation being less than 10% before Mg-Sn-Zn-Mn series magnesium alloy of the present invention solution treatment, can make this alloy in solution heat treatment process, form a large amount of very tiny twin.
4. Mg-Sn-Zn-Mn series magnesium alloy of the present invention is after solution treatment, and alloy microscopic structure is mainly single-phase-Mg, thus realization can be degradable.
5. Mg-Sn-Zn-Mn series magnesium alloy of the present invention is after solution treatment, and microstructure characteristic is include raised growth twin in single-phase-Mg crystal grain.In crystal grain, the existence of a large amount of tiny twin improves the obdurability of this alloy effectively, and wherein Mg-3Sn-1Zn-0.5Mn alloy has good comprehensive mechanical property (under room temperature, tensile strength is 211MPa, and unit elongation is up to 28%).
6. Mg-Sn-Zn-Mn series magnesium alloy of the present invention has lower hemolysis rate, wherein after the process of Mg-3Sn-1Zn-0.5Mn alloy solid solution, hemolysis rate is 4.68% (be less than 5%, meet the requirement of biomaterial hemolysis rate), be particularly suitable for being used as Biodegradable vascular inner bracket material.
Accompanying drawing explanation
Fig. 1 is the solution treatment state Mg-3Sn-1Zn-0.5Mn alloy microstructure figure described in the embodiment of the present invention 1.
Fig. 2 is the solution treatment state Mg-3Sn-1Zn-1Mn alloy microstructure figure described in the embodiment of the present invention 2.
Fig. 3 is the solution treatment state Mg-3Sn-0.5Zn-0.15Mn alloy microstructure figure described in the embodiment of the present invention 3.
Fig. 4 is the solution treatment state Mg-2Sn-1Zn-1Mn alloy microstructure figure described in the embodiment of the present invention 4.
Fig. 5 is the solution treatment state Mg-2Sn-1Zn-0.5Mn alloy microstructure figure described in the embodiment of the present invention 4.
Fig. 6 is the solution treatment state Mg-4Sn-0.5Zn-0.5Mn alloy microstructure figure described in the embodiment of the present invention 5.
Fig. 7 is the solution treatment state Mg-4Sn-1Zn-0.15Mn alloy microstructure figure described in the embodiment of the present invention 6.
Embodiment
Illustrate below and the present invention be described in more detail:
Embodiment 1:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-3Sn-1Zn-0.5Mn alloying constituent (nominal composition: Sn 3%, Zn 1%, Mn 0.5%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-3Sn-1Zn-0.5Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2extrude after carrying out homogenizing thermal treatment (homogenization temperature is 300 DEG C, and soaking time is 5 hours) in the heat treatment furnace of hybrid protection gas, extrusion deformation degree is 10%.Finally solution heat treatment (solid solution temperature is 450 DEG C, and soaking time is 24 hours, and stove is cold) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 238MPa, unit elongation 28%.Hemolysis rate is 4.68%.As shown in Figure 1, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-3Sn-1Zn-0.5Mn alloy microstructure that employing the present invention obtains.
Embodiment 2:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-3Sn-1Zn-1Mn alloying constituent (nominal composition: Sn 3%, Zn 1%, Mn 1%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-3Sn-1Zn-1Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2extrude after carrying out homogenizing thermal treatment (homogenization temperature is 300 DEG C, and soaking time is 5 hours) in the heat treatment furnace of hybrid protection gas, extrusion deformation degree is 5%.Finally solution heat treatment (solid solution temperature is 410 DEG C, and soaking time is 28 hours, air cooling) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 208MPa, unit elongation 23%.Hemolysis rate is 7.58%.As shown in Figure 2, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-3Sn-1Zn-1Mn alloy microstructure that employing the present invention obtains.
Embodiment 3:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-3Sn-0.5Zn-0.15Mn alloying constituent (nominal composition: Sn 3%, Zn0.5%, Mn 0.15%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-3Sn-0.5Zn-0.15Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2be rolled after carrying out homogenizing thermal treatment (homogenization temperature is 400 DEG C, and soaking time is 3 hours) in the heat treatment furnace of hybrid protection gas, rolling reduction is 10%.Finally solution heat treatment (solid solution temperature is 450 DEG C, and soaking time is 12 hours, air cooling) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 203MPa, unit elongation 27%.Hemolysis rate is 6.37%.As shown in Figure 3, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-3Sn-0.5Zn-0.15Mn alloy microstructure that employing the present invention obtains.
Embodiment 4:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-2Sn-1Zn-1Mn alloying constituent (nominal composition: Sn 2%, Zn 1%, Mn 1%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-2Sn-1Zn-1Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2be rolled after carrying out homogenizing thermal treatment (homogenization temperature is 300 DEG C, and soaking time is 3 hours) in the heat treatment furnace of hybrid protection gas, rolling reduction is 5%.Finally solution heat treatment (solid solution temperature is 420 DEG C, and soaking time is 18 hours, shrend) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 195MPa, unit elongation 24%.Hemolysis rate is 7.53%.As shown in Figure 4, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-2Sn-1Zn-1Mn alloy microstructure that employing the present invention obtains.
Embodiment 5:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-2Sn-1Zn-0.5Mn alloying constituent (nominal composition: Sn 2%, Zn 1%, Mn 0.5%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-2Sn-1Zn-0.5Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2be rolled after carrying out homogenizing thermal treatment (homogenization temperature is 300 DEG C, and soaking time is 3 hours) in the heat treatment furnace of hybrid protection gas, rolling reduction is 10%.Finally solution heat treatment (solid solution temperature is 420 DEG C, and soaking time is 24 hours, and stove is cold) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 205MPa, and unit elongation is up to 30%.Hemolysis rate is 5.38%.As shown in Figure 5, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-2Sn-1Zn-0.5Mn alloy microstructure that employing the present invention obtains.
Embodiment 6:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-4Sn-0.5Zn-0.5Mn alloying constituent (nominal composition: Sn 4%, Zn 0.5%, Mn 0.5%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-4Sn-0.5Zn-0.5Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2extrude after carrying out homogenizing thermal treatment (homogenization temperature is 400 DEG C, and soaking time is 5 hours) in the heat treatment furnace of hybrid protection gas, extrusion deformation degree is 5%.Finally solution heat treatment (solid solution temperature is 450 DEG C, and soaking time is 24 hours, and stove is cold) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 212MPa, unit elongation 29%.Hemolysis rate is 6.94%.As shown in Figure 6, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-4Sn-0.5Zn-0.5Mn alloy microstructure that employing the present invention obtains.
Embodiment 7:
Adopt pure magnesium ingot (purity is not less than 99.96%), pure tin ingot (purity is not less than 99.95%), pure zinc ingot (purity is not less than 99.95%) and Mg-6.8%Mn master alloy, by Mg-4Sn-1Zn-0.15Mn alloying constituent (nominal composition: Sn 4%, Zn 1%, Mn 0.15%, Impurity Fe < 0.002%, Cu < 0.002% and Ni < 0.002%, surplus is Mg) alloyage, under RJ-2 flux protection, first pure magnesium ingot is melted in resistance furnace, Mg-Mn master alloy is added when temperature is raised to 750 DEG C, stir 10 minutes after its fusing, add pure tin and pure zinc subsequently, stir 10 ~ 15 minutes, to make alloy element Mn, Sn and zinc homogenizing.Then carry out refining at 730 DEG C, refining agent is RJ-5 flux (being about 2% of quality of furnace charge), and drags for the end and stir 10 minutes.Be warming up to 750 DEG C more subsequently, insulation leaves standstill 20 ~ 60 minutes, is finally cooled to 720 DEG C, drags for aluminium alloy surface scum, at SF
6/ CO
2be poured under mixed gas protected in metal mold and carry out gravitational casting.Before solution heat treatment, first predeformation is carried out to above-mentioned Mg-4Sn-1Zn-0.15Mn alloy cast ingot.Predeformation technique is, is connected with SF being put into by above-mentioned alloy cast ingot
6/ CO
2extrude after carrying out homogenizing thermal treatment (homogenization temperature is 400 DEG C, and soaking time is 5 hours) in the heat treatment furnace of hybrid protection gas, extrusion deformation degree is 10%.Finally solution heat treatment (solid solution temperature is 450 DEG C, and soaking time is 26 hours, and stove is cold) is carried out to the alloy after above-mentioned predeformation.This Alloy At Room Temperature tensile strength is 217MPa, unit elongation 27%.Hemolysis rate is 7.16%.As shown in Figure 7, as can be seen from the figure this alloy microscopic structure is characterized as in single-phase-Mg crystal grain and includes raised growth twin the solution treatment state Mg-4Sn-1Zn-0.15Mn alloy microstructure that employing the present invention obtains.