Summary of the invention
The high-strength magnesium alloy that the purpose of this invention is to provide a kind of heat treatment reinforcement has overcome existing magnesium alloy rare-earth addition height, complicated process of preparation and the problem with high costs that causes.
Technical scheme of the present invention is that a kind of high-strength magnesium alloy of heat treatment reinforcement according to mass percent, is made up of following each component: Gd:3-8%, Y:1-6%, Zn:0.5-3.5%, Mn:0.5-2.5%, Zr≤1.0%, all the other are Mg, above each component mass percent summation is 100%.
Characteristics of the present invention also are,
The mass percent summation of Gd and Y was not more than 10% of total mass mark during component was formed.
The present invention also provides the preparation method of above-mentioned magnesium alloy, carries out according to following steps:
Step 1, get prior hole-drilled magnesium ingot, Mg-Gd master alloy, Mg-Y master alloy, technical pure Zn ingot, Mn powder and Mg-Zr master alloy respectively, make that relationship between quality satisfies following mass percent: Gd:3-8% between each material, Y:1-6%, Zn:0.5-3.5%, Mn:0.5-2.5%, Zr≤1.0%, all the other are Mg, and component form in the mass percent summation of Gd and Y be not more than 10% of total mass mark;
Step 2, the Mn powder that step 1 is taken by weighing places the prior hole well of boring on the magnesium ingot, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 720-750 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 785-800 ℃, add the Mg-Zr master alloy, and mechanical stirring 10-15 minute, molten metal is cooled to 720-740 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 745-785 ℃ and carry out refining treatment, temperature is adjusted to 750-760 ℃ again, pour in the bottom filling metal mold of preheating, obtain magnesium alloy ingot;
Step 3, the magnesium alloy ingot that step 2 is obtained is incubated 6-18 hour at 450-520 ℃, cools off in air then, in 6-24 hour ageing treatment of 220-300 ℃ of insulation, is crushed to bar at last more afterwards.
Wherein the Mn powder directly is the 50-200 order in the step 1.
Wherein flux adopts industrial RJ-2 flux in the step 2, and the addition of solvent is the 5-10% of institute's molten alloy quality.
Wherein the preheating temperature of bottom filling metal mold is 350 ℃ ± 10 ℃ in the step 2.
Extrusion ratio when wherein being crushed to bar in the step 3 is 1: 5-20, extrusion temperature are 260-350 ℃.
The invention has the beneficial effects as follows, make the alloy microtexture possess long period stacking order structure by appropriate alloying and preferred thermal treatment process, the alloy ree content is few, density is low, cheap, simple to operate, both had the room temperature high strength, under hot conditions, also had excellent mechanical performances.
Embodiment
The present invention is described in detail below in conjunction with embodiment.
The invention provides a kind of high-strength magnesium alloy of heat treatment reinforcement, according to mass percent, formed by following each component: Gd:3-8%, Y:1-6%, Zn:0.5-3.5%, Mn:0.5-2.5%, Zr≤1.0%, all the other are Mg, above each component mass percent summation is 100%.Wherein the mass percent summation of Gd and Y is not more than 10% of total mass mark.
The present invention also provides the preparation method of above-mentioned magnesium alloy, carries out according to following steps:
Step 1, get prior hole-drilled magnesium ingot, Mg-Gd master alloy, Mg-Y master alloy, technical pure Zn ingot, Mn powder and Mg-Zr master alloy respectively, make that relationship between quality satisfies following mass percent: Gd:3-8% between each material, Y:1-6%, Zn:0.5-3.5%, Mn:0.5-2.5%, Zr≤1.0%, all the other are Mg, and component form in the mass percent summation of Gd and Y be not more than 10% of total mass mark;
Step 2, the 50-200 purpose Mn powder that step 1 is taken by weighing places the prior hole well of boring on the magnesium ingot, 5-10% according to the molten alloy quality takes by weighing industrial RJ-2 flux, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 720-750 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 785-800 ℃, add the Mg-Zr master alloy, and mechanical stirring 10-15 minute, molten metal is cooled to 720-740 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, then the alloy liquid temp is risen to 745-785 ℃ and carry out refining treatment, temperature is adjusted to 750-760 ℃ again, pours into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot;
Step 3, the magnesium alloy ingot that step 2 is obtained is incubated 6-18 hour at 450-520 ℃, cools off in air then, afterwards in 6-24 hour ageing treatment of 220-300 ℃ of insulation, be crushed to bar at last again, extrusion ratio is 1: 5-20, extrusion temperature are 260-350 ℃.
Embodiment 1
Alloying constituent consists of by mass percentage: 3%Gd, and 4%Y, 3.5%Zn, 1.5%Mn, 0.8%Zr, all the other are Mg and unavoidable impurities.
Alloy casting technology is: the 50-200 purpose Mn powder that at first will take by weighing places and bores good hole on the magnesium ingot in advance, take by weighing industrial RJ-2 flux according to 5% of molten alloy quality, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 720 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 790 ℃, add the Mg-Zr master alloy, and mechanical stirring 10 minutes, molten metal is cooled to 720 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 760 ℃ and carry out refining treatment, temperature is adjusted to 750 ℃ again, pour into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot.
The cast alloy thermal treatment process is: with 520 ℃ of solution treatment of magnesium alloy ingot 18 hours, cool off in air then, afterwards 220 ℃ of isothermal agings 24 hours.By being crushed to bar, its extrusion ratio is 1: 5 then, and extrusion temperature is 310 ℃.Still have long period stacking order structure in its microstructure of the extruded bars that obtains, the shared matrix area ratio of this structure is 65%.
The high-strength magnesium alloy of present embodiment gained, its room temperature tensile strength is 361MPa, unit elongation is 8%.
Embodiment 2
Alloying constituent consists of by weight percentage: 5%Gd, and 4%Y, 1%Zn, 1.5%Mn, 0.8%Zr, all the other are Mg and unavoidable impurities.
Alloy casting technology is: the 50-200 purpose Mn powder that step 1 is taken by weighing places the prior hole well of boring on the magnesium ingot, take by weighing industrial RJ-2 flux according to 7% of molten alloy quality, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 740 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 785 ℃, add the Mg-Zr master alloy, and mechanical stirring 15 minutes, molten metal is cooled to 730 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 745 ℃ and carry out refining treatment, temperature is adjusted to 755 ℃ again, pour into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot;
The cast alloy thermal treatment process is: magnesium alloy ingot 450 ℃ of solution treatment 10 hours, is cooled off then 260 ℃ of isothermal agings 8 hours in air.By being crushed to bar, its extrusion ratio is 1: 10 then, and extrusion temperature is 350 ℃.Still have long period stacking order structure in its microstructure of the extruded bars that obtains, the shared matrix area ratio of this structure is 70%.
The high-strength heat-resistant magnesium alloy of present embodiment gained, its room temperature tensile strength is 382MPa, unit elongation is 6%.
Embodiment 3
Alloying constituent consists of by weight percentage: 8%Gd, and 1%Y, 1%Zn, 0.5%Mn, 0.8%Zr, all the other are Mg and unavoidable impurities.
Alloy casting technology is: the 50-200 purpose Mn powder that step 1 is taken by weighing places the prior hole well of boring on the magnesium ingot, take by weighing industrial RJ-2 flux according to 10% of molten alloy quality, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 750 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 800 ℃, add the Mg-Zr master alloy, and mechanical stirring 13 minutes, molten metal is cooled to 740 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 785 ℃ and carry out refining treatment, temperature is adjusted to 760 ℃ again, pour into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot;
The cast alloy thermal treatment process is: magnesium alloy ingot 520 ℃ of solution treatment 6 hours, is cooled off then 240 ℃ of isothermal agings 6 hours in air.By being crushed to bar, its extrusion ratio is 1: 20 then, and extrusion temperature is 300 ℃.Still have long period stacking order structure in its microstructure of the extruded bars that obtains, the shared matrix area ratio of this structure is 75%.
The high-strength heat-resistant magnesium alloy of present embodiment gained, its room temperature tensile strength is 396MPa, unit elongation is 8%.
Embodiment 4
Alloying constituent consists of by weight percentage: 6%Gd, and 4%Y, 0.5%Zn, 1.5%Mn, 0.8%Zr, all the other are Mg and unavoidable impurities.
Alloy casting technology is: the 50-200 purpose Mn powder that at first will take by weighing places and bores good hole on the magnesium ingot in advance, take by weighing industrial RJ-2 flux according to 5% of molten alloy quality, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 720 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 790 ℃, add the Mg-Zr master alloy, and mechanical stirring 10 minutes, molten metal is cooled to 720 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 760 ℃ and carry out refining treatment, temperature is adjusted to 750 ℃ again, pour into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot.
The cast alloy thermal treatment process is: magnesium alloy ingot 480 ℃ of solution treatment 12 hours, is cooled off then 260 ℃ of isothermal agings 8 hours in air.By being crushed to bar, its extrusion ratio is 1: 12.5 then, and extrusion temperature is 260 ℃.Still have long period stacking order structure in its microstructure of the extruded bars that obtains, the shared matrix area ratio of this structure is 75%.
The high-strength heat-resistant magnesium alloy of present embodiment gained, its room temperature tensile strength is 416MPa, unit elongation is 6.1%.
Embodiment 5
Alloying constituent consists of by weight percentage: 4%Gd, and 6%Y, 1%Zn, 2.5%Mn, 0.6%Zr, all the other are Mg and unavoidable impurities.
Alloy casting technology is: the 50-200 purpose Mn powder that at first will take by weighing places and bores good hole on the magnesium ingot in advance, take by weighing industrial RJ-2 flux according to 5% of molten alloy quality, sprinkle flux at magnesium ingot, and together put into well formula resistance furnace and melt, and make the magnesium liquid temp rise to 720 ℃, added Mg-Y and Mg-Gd master alloy mechanical stirring again 15 minutes, then the molten metal temperature is risen to 790 ℃, add the Mg-Zr master alloy, and mechanical stirring 10 minutes, molten metal is cooled to 720 ℃ at last, added technical pure Zn ingot and mechanical stirring 10 minutes, and then the alloy liquid temp was risen to 760 ℃ and carry out refining treatment, temperature is adjusted to 750 ℃ again, pour into preheating temperature and be in 350 ℃ ± 10 ℃ the bottom filling metal mold, obtain magnesium alloy ingot.
The cast alloy thermal treatment process is: with magnesium alloy ingot at 10 hours air coolings of 500 ℃ of solution treatment, 300 ℃ of isothermal agings 8 hours.By being crushed to bar, its extrusion ratio is 1: 12.5 then, and extrusion temperature is 300 ℃.Still have long period stacking order structure in its microstructure of the extruded bars that obtains, the shared matrix area ratio of this structure is 75%.
The high-strength heat-resistant magnesium alloy of present embodiment gained, its room temperature tensile strength is 405MPa, unit elongation is 5.2%.
The present invention, compares with the magnesium alloy that prior art is prepared again through the high-strength magnesium alloy of thermal treatment and crimp preparation by common founding, and the total amount of added rare earth is obviously little, thus the cost of alloy reduction, and be interpolation Mn in this alloy; Melting technology of the present invention, thermal treatment process and follow-up processing all have notable difference with prior art in addition, and the alloy room temperature strength that obtains obviously is better than the magnesium alloy that prior art for preparing goes out.
In a word, the present invention adopts and adds rare earth element Gd, Y, but add-on much smaller than existing patent and document, purpose is by technological measures such as appropriate alloying and preferred thermal treatment reduction cost of alloy, gives full play to magnesium alloy low density structures properties of materials.
Among the present invention after heat treatment the area percentage of the shared crystal grain of formed long period stacking order structure more than 90%.
Middle-weight rare earths Gd of the present invention, Y add with Mg-Gd, Mg-Y master alloy respectively.The adding of Gd, Y all can be played the effect of refinement microtexture, and Y, the Gd solid solubility in Mg is very big, can improve the mechanical property of alloy by solution strengthening and aging precipitation precipitation strength.
The a spot of Mn of interpolation, Zr element have not only improved plasticity and the hot workability of alloy among the present invention, and because the partial solid solubility of Zr in magnesium, Zr can be used as heterogeneous forming core core crystal grain thinning, and Zr adopts Mg-Zr master alloy mode to add, and Mn can also improve the creep-resistant property of alloy.
Add cheap Zn element among the present invention, not only can form Mg7Zn3 and MgZn strengthening phase with magnesium, and form rare earth compound reinforcement crystal boundary with Gd, Y rare earth element.Can form long period stacking order structure by spinodal decomposition by rational heat treatment Gd, Y, Zn, Mg atom in addition, this structure has been proved and can have obviously improved the intensity of alloy and the thermostability of alloy.
By adjusting each component proportioning, use common founding and can prepare cheap high strength, low density magnesium alloy by rational heat treatment technology and crimp among the present invention.This magnesium alloy not only has excellent room temperature high-strong toughness and high temperature tensile properties, and has plastic deformation ability and hot workability preferably.Its room temperature tensile strength 350-410MPa, unit elongation 5-15%.