METHOD FOR PREPARING AMORPHOUS PARTICLE-MODIFIED MAGNESIUM ALLOY SURFACE-GRADIENT COMPOSITES

Abstract

The invention relates to a method for preparing amorphous particle-modified magnesium alloy surface-gradient composites and pertains to the technical field of composites. The method comprises steps of: holding the temperature at 150˜350° C. for FeCrMoBC amorphous alloy particles; mixing pure magnesium, pure zinc, pure aluminum, pure copper and Mg-5 wt % Mn alloy under continuous protective gases, gradually raising temperature to 720˜760° C. and melting at a constant temperature for 15˜25 min to obtain a magnesium alloy melt; cooling the magnesium alloy melt to 600˜635° C. and starting mechanical stirring; continuing the cooling until the semi-solid temperature is 570˜615° C., slowly adding the above FeCrMoBC amorphous alloy particles, holding for 2˜5 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified magnesium alloy surface-gradient composite.

Claims

1. A method for preparing amorphous particle-modified magnesium alloy surface-gradient composites, wherein the method comprises steps of: S1 weighing pure magnesium, pure zinc, pure aluminum, pure copper, Mg-5 wt % Mn alloy, and FeCrMoBC amorphous alloy particles; S2 holding the temperature at 150˜350° C. for the FeCrMoBC amorphous alloy particles weighed at step (1); S3 mixing the pure magnesium, pure zinc, pure aluminum, pure copper, and Mg-5 wt % Mn alloy weighed at step (1), putting the mixture in a melting and heating furnace under continuous protective gases, gradually raising temperature to 720˜760° C. and melting at a constant temperature for 15˜25 min to obtain a magnesium alloy melt; and S4 cooling the magnesium alloy melt obtained at step (3) to 600˜635° C., starting mechanical stirring till the temperature is cooled to 570˜615° C., slowly adding the FeCrMoBC amorphous alloy particles obtained at step (2), holding for 2˜5 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified magnesium alloy surface-gradient composite.

2. The method for preparing amorphous particle-modified magnesium alloy surface-gradient composites according to claim 1, wherein supposing that the total mass of the raw materials at step (1) is 100%, the pure magnesium is 72.85˜85.35%, the pure zinc is 7.50˜8.50%, the pure aluminum is 0.65˜9.50%, the pure copper is 0.45˜0.55%, the Mg-5 wt % Mn alloy is 9.0˜11.0%, and the FeCrMoBC amorphous alloy particles are 2.00˜8.00%.

3. The method for preparing amorphous particle-modified magnesium alloy surface-gradient composites according to claim 1, wherein the protective gases at step (3) are mixed gases of CO2 and SF6.

4. The method for preparing amorphous particle-modified magnesium alloy surface-gradient composites according to claim 3, wherein the volume fraction of CO2 in the protective gases at step (3) is 99%.

5. The method for preparing amorphous particle-modified magnesium alloy surface-gradient composites according to claim 1, wherein the mechanical stirring speed at step (3) is 350˜1000 rpm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a microstructure diagram of an amorphous particle-modified AZ91 surface-gradient composite in Embodiment 1;

[0021] FIG. 2 is an EDS diagram of an amorphous particle-modified AZ91 surface-gradient composite in Embodiment 1;

[0022] FIG. 3 is a microstructure diagram of an amorphous particle-modified AM50 surface-gradient composite in Embodiment 2;

[0023] FIG. 4 is a microstructure diagram of an amorphous particle-modified AM60 surface-gradient composite in Embodiment 3;

[0024] FIG. 5 is a microstructure diagram of an amorphous particle-modified ZA81 surface-gradient composite in Embodiment 4.

DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with specific embodiments, but the scope of protection of the present invention is not limited to the contents below.

[0026] Embodiment 1: A method for preparing an amorphous particle-modified AZ91 magnesium alloy surface-gradient composite, with steps of:

[0027] (1) weighing pure magnesium, pure zinc, pure aluminum, Mg-5 wt % Mn alloy, and FeCrMoBC amorphous alloy particles, wherein supposing that the total mass of the raw materials is 100%, the pure magnesium is 73.60%, the pure aluminum is 9.50%, the pure zinc is 0.90%, the Mg-5 wt % Mn alloy is 8.00%, and the FeCrMoBC amorphous alloy particles are 8.00%;

[0028] (2) holding the temperature at 300° C. for the FeCrMoBC amorphous alloy particles weighed at step (1);

[0029] (3) mixing the pure magnesium, pure zinc, pure aluminum, and Mg-5 wt % Mn alloy weighed at step (1), putting the mixture in a melting and heating furnace under continuous protective gases (mixed gases of CO.sub.2 and SF.sub.6), gradually raising temperature to 760° C. and melting at a constant temperature for 20 min to obtain a magnesium alloy melt, wherein the volume fraction of CO.sub.2 in the protective gases is 99%; and

[0030] (4) cooling the magnesium alloy melt at step (3) to 600° C., starting mechanical stirring (the stirring speed is 1,000 rpm), continuing to cool it to 570° C., slowly adding the FeCrMoBC amorphous alloy particles obtained at step (2), holding for 3 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified AZ91 magnesium alloy surface-gradient composite;

[0031] The microstructure diagram of the amorphous particle-modified ZA91 surface-gradient composite in this embodiment is shown in FIG. 1, and the EDS diagram of the amorphous particle-modified ZA91 surface-gradient composite is shown in FIG. 2. From FIG. 1 and FIG. 2, it can be known that the amorphous particles show a gradient distribution in the alloy matrix and the interfacial bonding is good.

[0032] Embodiment 2: A method for preparing an amorphous particle-modified AM50 magnesium alloy surface-gradient composite, with steps of:

[0033] (1) weighing pure magnesium, pure zinc, pure aluminum, Mg-5 wt % Mn alloy, and FeCrMoBC amorphous alloy particles, wherein supposing that the total mass of the raw materials is 100%, then the pure magnesium is 82.70%, the pure aluminum is 5.00%, the pure zinc is 0.30%, the Mg-5 wt % Mn alloy is 10.00%, and the FeCrMoBC amorphous alloy particles are 2.00%;

[0034] (2) holding the temperature at 250° C. for the FeCrMoBC amorphous alloy particles weighed at step (1);

[0035] (3) mixing the pure magnesium, pure zinc, pure aluminum, and Mg-5 wt % Mn alloy weighed at step (1), putting the mixture in a melting and heating furnace under continuous protective gases (mixed gases of CO.sub.2 and SF.sub.6), gradually raising temperature to 720° C. and smelting at constant temperature for 20 min to obtain a magnesium alloy melt, wherein the volume fraction of CO.sub.2 in the protective gases is 99%; and

[0036] (4) cooling the magnesium alloy melt at step (3) to 625° C., starting mechanical stirring (the stirring speed is 350 rpm), continuing to cool it to 605° C., slowly adding the FeCrMoBC amorphous alloy particles obtained at step (2), holding for 3 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified AM50 magnesium alloy surface-gradient composite;

[0037] The microstructure diagram of the amorphous particle-modified AM50 surface-gradient composite in this embodiment is shown in FIG. 3. From FIG. 3, it can be known that the amorphous particles show a gradient distribution at the bottom and good dispersibility in the same layer.

[0038] Embodiment 3: A method for preparing an amorphous particle-modified AM60 magnesium alloy surface-gradient composites, with steps of:

[0039] (1) weighing pure magnesium, pure zinc, pure aluminum, Mg-5 wt % Mn alloy, and FeCrMoBC amorphous alloy particles, wherein supposing that the total mass of the raw materials is 100%, then the pure magnesium is 78.70%, the pure aluminum is 5.00%, the pure zinc is 0.30%, Mg-5 wt % Mn alloy is 10.00%, and the FeCrMoBC amorphous alloy particles are 6.00%;

[0040] (2) holding the temperature at 250° C. for the FeCrMoBC amorphous alloy particles weighed at step (1);

[0041] (3) mixing the pure magnesium, pure zinc, pure aluminum and Mg-5 wt % Mn alloy weighed at step (1), putting the mixture in a smelting and heating furnace under continuous protective gases (mixed gases of CO.sub.2 and SF.sub.6), gradually raising temperature to 720° C. and smelting at constant temperature for 20 min to obtain a magnesium alloy melt, wherein the volume fraction of CO.sub.2 in the protective gases is 99%; and

[0042] (4) cooling the magnesium alloy melt at step (3) to 620° C., starting mechanical stirring (the stirring speed is 350 rpm), continuing to cool it to 600° C., slowly adding the FeCrMoBC amorphous alloy particles obtained at step (2), holding for 2 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified AM60 magnesium alloy surface-gradient composite;

[0043] The microstructure diagram of the amorphous particle-modified AM60 surface-gradient composite in this embodiment is shown in FIG. 4. From FIG. 4, it can be known that a good gradient distribution is shown along the gravity direction, and the dispersibility is good, too.

[0044] Embodiment 4: A method for preparing an amorphous particle-modified ZA81 magnesium alloy surface-gradient composite, with steps of:

[0045] (1) weighing pure magnesium, pure zinc, pure aluminum, pure copper, Mg-5 wt % Mn alloy, and FeCrMoBC amorphous alloy particles, wherein supposing that the total mass of the raw materials is 100%, then the pure magnesium is 75.85%, the pure zinc is 8.00%, the pure aluminum is 0.65%, the pure copper is 0.5%, Mg-5 wt % Mn alloy is 10.00%, and the FeCrMoBC amorphous alloy particles are 5.00%;

[0046] (2) holding the temperature at 300° C. for the FeCrMoBC amorphous alloy particles weighed at step (1);

[0047] (3) mixing the pure magnesium, pure zinc, pure aluminum, and Mg-5 wt % Mn alloy weighed at step (1), putting the mixture in a melting and heating furnace under continuous protective gases (mixed gases of CO.sub.2 and SF.sub.6), gradually raising temperature to 760° C. and melting at a constant temperature for 20 min to obtain a magnesium alloy melt, wherein the volume fraction of CO.sub.2 in the protective gases is 99%; and

[0048] (4) cooling the magnesium alloy melt at step (3) to 610° C., starting mechanical stirring (the stirring speed is 1,000 rpm), continuing to cool it to 590° C., slowly adding the FeCrMoBC amorphous alloy particles obtained at step (2), holding for 5 min after mixing evenly, and cooling the crucible with water to obtain an amorphous particle-modified ZA81 magnesium alloy surface-gradient composite;

[0049] The microstructure diagram of the amorphous particle-modified ZA81 surface-gradient composite in this embodiment is shown in FIG. 5. From FIG. 5, it can be known that after settlement, the amorphous particles show a gradient distribution in a specific thickness.

[0050] The semi-solid temperature interval mentioned in Embodiments 1-4 is determined by the following method: according to the magnesium alloy phase diagram, the temperature interval is from the initial solidification temperature (To) to the temperature (Tso) when the weight percentage of the liquid phase in the melt is approximately 50%. The table below shows the semi-solid temperature intervals of magnesium alloys AZ91, AM50, AM60, and ZA81:

TABLE-US-00001 Weight percentage of the Alloys T.sub.0 (° C.) T.sub.50 (° C.) liquid phase in alloy AZ91 600 570 53% AM50 625 605 46% AM60 620 600 50% ZA81 610 590 51%

[0051] Above the specific embodiments of the present invention are described in details in conjunction with accompanying drawings, but the present invention is not limited to the above embodiments. Variations can be made within the knowledge of those of ordinary skill in the art without departing from the spirit of the present invention.