METHOD AND APPARATUS FOR CASTING A MATERIAL COMPRISING OF NANO-MICRO DUPLEX GRAIN STRUCTURE

Abstract

A method and apparatus casts a material with nano-micro duplex grain structure. The apparatus is comprised of module system, heating system, casting mold and gating system, multiaxial compound motion system accompanied by the following technological characteristics; alloy smelting; after heat preservation, alloy melt are poured into the casting mold which is put into the centrifugal barrel of the six-axis motion system; then the casting mold carries out composite motion and the alloy melt starts solidification; as a result, casting AlSi alloy block with multi-scale nano-structure comprising of nano-micro duplex grain group are prepared. The advantages of the present invention includes that multi-scale casting nano-structure with nano-micro duplex grain group are obtained because of the composite shear flow field generated in the alloy melt.

Claims

1. An apparatus for casting materials with nano-micro duplex grain group, comprising: a cabin system, a smelting system, a pouring system, a casting mold, a rotating plate, a coupling shaft I, a coupling shaft II, an intermediate coupling seat, a coupling shaft III, a coupling shaft IV, a bottom support seat, a six-axis motion system I, a six-axis motion system II, and a centrifugal barrel; wherein the casting mold is settled in the centrifugal barrel; the centrifugal barrel is linked with the six-axis motion system I via the rotating plate and the coupling shaft I; the six-axis motion system I is linked with the six-axis motion system II via the coupling shaft II, the intermediate coupling seat and the coupling shaft III; the six-axis motion system II is fixed on the bottom support seat via the coupling shaft IV; six-axis motion primitive of each single six-axis motion system is corresponding to six motors under which the rotating plate moves respectively along six axis, that are vertical motions along three kinds directions including x-axis, y-axis and z-axis; R represents rotating motion of the rotating plate, M represents vertical motion perpendicular to the direction of the rotating plate, T represents inclinable motion of the rotating plate and represents inclinable angle of the rotating plate; the number of the set of six-axis motion system is up to the requirement.

2. An apparatus as recited in claim 1, wherein the rotating plate of the six-axis motion primitive rotates along the path whose parameters are in the following limitation: R=180+180, X==2500 mm+2500 mm, Y=2500 mm+2500 mm, Z=01000 mm, T=80+80, M=0 mm1000 mm.

3. An apparatus as recited in claim 1, wherein the distance of the six-axis motion system I is R.sub.1=03000 mm and the distance of the six-axis motion system II is R.sub.2=03000 mm.

4. A method for casting materials with nano-micro duplex grain group prepared by the apparatus as recited in claim 1, comprising: (1) preparing metal and alloy; (2) putting the metal and alloy into the crucible of the melting system; placing the casting mold in the centrifugal bucket; filling the refractory insulation material around the casting mold; (3) heating the metal and alloy in the crucible to a default temperature and keeping the temperature for a default time, and then pouring metal liquid into the preheated casting mold; (4) driving the six-axis motion systems to force the centrifugal barrel to move according to the set path, and then cooling the metal liquid down.

5. A method as recited in claim 4, wherein during the process of pouring metal liquid into the preheated casting mold, the superheat degree is controlled according to components of the metal, and during the process of cooling the metal liquid down, the condenser depression is controlled according to components of the metal; strong composite shear flow is formed in the metal liquid with the motion of the casting mold that is put into the six-axis motion systems.

6. A method as recited in claim 4, wherein the applicable material of the metal are nickel, aluminum, iron, copper and titanium, or alloy of the nickel, aluminum, iron, copper and titanium thereof, or intermetallic compound of titanium aluminum, intermetallic compound of iron aluminum, intermetallic compound of nickel aluminum.

7. A method as recited in claim 4, wherein the processes of melting and casting are carried out in vacuum or non-vacuum.

8. A casting AlSi alloy block with multi-scale nano-structure prepared via the method for casting materials with nano-micro duplex grain group as recited in claim 4, comprising: silicon of 2 wt % 12 wt %; superheat degree from 50 C. to 100 C. during the process of casting; condenser depression from 0.1 C. to 50 C. during the process of cooling; strong composite shear flow formed in the metal liquid with the motion of the casting mold that is put into the six-axis motion systems; grain of the size from 10 nm to 5000 nm in the aluminum matrix phase; grain of the size from 10 nm to 10 m in the eutectic silicon phase.

9. A method as recited in claim 4, wherein a large number of second-phase nano-silicon particles are distributed in the aluminum matrix phase and the sizes of nano-silicon particles are between 1 nm to 100 nm.

Description

DESCRIPTION OF THE DRAWINGS

[0033] The above and further advantages of the invention may be better understood by referring to the following description with the accompanying drawings, in which:

[0034] FIG. 1 is a schematic diagram of composition of the composite motion equipment in accordance with one embodiment of the present invention; wherein,

[0035] 1cabin system, 2smelting system, 3pouring system, 4casting mold, 5rotating plate, 6coupling shaft I, 7coupling shall II, 8intermediate coupling seat, 9coupling shall III, 10coupling shaft IV, 11bottom support seat, 12six-axis motion system I, 13six-axis motion system II, 14-centrifugal barrel.

[0036] FIG. 2 is a motion schematic diagram of a single six-axis motion system in accordance with one embodiment of the present invention; wherein the distance between two sets of six-axis motion system and system connecting shaft bracket is a.

[0037] FIG. 3 is morphologies of a low magnification SEM morphology and high magnification TEM morphologies of the cross section of Al-7 wt % Si alloy; wherein, (a) is a SEM morphology of the cross section of Al-7 wt % Si alloy processed by composite shear motion in which the alloy is composed of white aluminum matrix phase and black silicon phase. (b) is a TEM morphology of one amplified region of the white aluminum matrix phase at the point of position A in figure (a), wherein the -Al matrix is composed of white large aluminum grains (grain sizes from several hundred nm to several m) and the black grain boundary region surrounding thereof; (c) is a TEM morphology of another amplified region of the white aluminum matrix phase at the point of position A in figure (a), wherein the size of the -Al matrix is about several hundred nm; (d) is the morphologies of the Si particles distributed in small size aluminum grains in figure (c) and the eutectic structure between two small size aluminum grains in figure (c), which is represented by a dotted line and the spacing of which is about 12 nm.

[0038] FIG. 4 is a comparison-curve graph of stress and strain in tensile engineering of Al-7 wt % Si alloys prepared respectively via casting under strong convection and conventional casting. The tensile strength is increased by more than 70% and the elongation is increased by more than three times.

[0039] FIG. 5 is comparison SEM morphologies of fracture of Al-7 wt % Si alloys prepared respectively via casting under strong convection and conventional casting. (a) shows the cleavage fracture of the Al-7 wt % Si alloy by the traditional casting and it can be seen that the tearing edges separate large pieces of cleavage surface; (b) shows the decrease of cleavage surface of Al-7 wt % Si alloy prepared by casting under strong convection and dimples appear at the tensile fracture.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0040] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

[0041] Embodiment 1:

[0042] Taking Al-7 wt % Si alloy as an example, nano-micro mixed grains are obtained after metal solidification. Industrial pure aluminum with the pure of 99.8% and industrial pure silicon with the pure of 99.9% are put into one graphite crucible as shown in FIG. 1, and then the materials in the graphite crucible are melting by a medium frequency induction furnace with the condition of vacuum degree of 6.010.sup.2 Pa in furnace chamber, filling the gas of high purity Ar and the pressure of furnace chamber of 0.04 MPa. The metal in the graphite crucible are heated rapidly until the temperature reaches 1000 C. that should be kept for 1 hour, and then cooled to 750 C. and poured into a rectangle graphite casting mold with internal size of 70 mm80 mm110 mm and the thickness of 10 mm which is preheated to 250 C., making sure that the degree of superheat to maintain between 50 C. to 100 C. during the whole casting process while the degree of supercooling of the metal could be between 0.1 C. to 50 C. during the process of solidification. The casting mold should be sealed by a cover in order to prevent metal liquid from spilling as a preference.

[0043] The parameters of the equipment in FIG. 1 and FIG. 2 are settled as follows: X=0 mm, Y=0 mm, Z=0 mm, T=0, M=0 mm. In six-axis motion system II (13), the R parameter is not fixed but continuous, which is corresponding to the radius of the disk of R.sub.1=150 mm and the rotation speed of the disk of n.sub.1=75 rpm; in the six-axis motion system I (12), the R parameter is also not fixed but continuous, which is corresponding to the radius of the disk of R.sub.2=100 mm and the rotation speed of the disk of n.sub.2=450 rpm. The alloy liquid is treated by the strong convection in 15 minutes after poured into the casting mold and then removed after it is cooled. FIG. 3, FIG. 4 and FIG. 5 show the morphologies of low-power scanning and high-power transmission of the cross section, a curve graph of stress and strain in tensile engineering and morphology of stretched fracture of Al-7 wt % Si alloy prepared via casting under strong convection. It can be seen that the casting Al-7 wt % Si alloy is compositing of nano-micro duplex grain group.

[0044] Embodiment 2:

[0045] Taking Al-7 wt % Si alloy as an example, nano-micro mixed grains are obtained after metal solidification. Industrial pure aluminum with the pure of 99.8% and industrial pure silicon with the pure of 99.9% are put into one graphite crucible as shown in FIG. 1, and then the materials in the graphite crucible are melting by a medium frequency induction furnace with the condition of vacuum degree of 6.010.sup.2 Pa in furnace chamber, filling the gas of high purity Ar and the pressure of furnace chamber of 0.04 Mpa. The metal in the graphite crucible are heated rapidly until the temperature reaches 1000 C. that should be kept for 1 hour, and then cooled to 750 C. and poured into a rectangle graphite casting mold with internal size of 70 mm80 mm110 mm and the thickness of 10 mm which is preheated to 250 C., making sure that the degree of superheat to maintain between 50 C. to 100 C. during the whole casting process while the degree of supercooling of the metal could be between 0.1 C. to 50 C. during the process of solidification. The casting mold should be sealed by a cover in order to prevent metal liquid from spilling as a preference.

[0046] In six-axis motion system II (13), the R parameter is not fixed but continuous, which is corresponding to the radius of the disk of R.sub.1=150 mm and the rotation speed of the disk of n.sub.1=100 rpm; in the six-axis motion system I (12), the R parameter is also not fixed but continuous, which is corresponding to the radius of the disk of R.sub.2=100 mm and the rotation speed of the disk of n.sub.2=100 rpm. The alloy liquid is treated by the strong convection in 15 minutes after poured into the casting mold and then removed after it is cooled.

[0047] Embodiment 3:

[0048] Taking Al-7 wt % Si alloy as an example, nano-micro mixed grains are obtained after metal solidification. Industrial pure aluminum with the pure of 99.8% and industrial pure silicon with the pure of 99.9% are put into one graphite crucible as shown in FIG. 1, and then the materials in the graphite crucible are melting by a medium frequency induction furnace with the condition of vacuum degree of 6.010.sup.2 Pa in furnace chamber, filling the gas of high purity Ar and the pressure of furnace chamber of 0.04 Mpa. The metal in the graphite crucible are heated rapidly until the temperature reaches 1000 C. that should be kept for 1 hour, and then cooled to 750 C. and poured into a rectangle graphite casting mold with internal size of 70 mm80 mm110 mm and the thickness of 10 mm which is preheated to 250 C., making sure that the degree of superheat to maintain between 50 C. to 100 C. during the whole casting process while the degree of supercooling of the metal could be between 0.1 C. to 50 C. during the process of solidification. The casting mold should be sealed by a cover in order to prevent metal liquid from spilling as a preference.

[0049] In six-axis motion system II (13), the R parameter is not fixed but continuous, which is corresponding to the radius of the disk of R.sub.1=150 mm and the rotation speed of the disk of n.sub.1=100 rpm; in the six-axis motion system I (12), the R parameter is also not fixed but continuous, which is corresponding to the radius of the disk of R.sub.2=100 mm and the rotation speed of the disk of n.sub.2=500 rpm. The alloy liquid is treated by the strong convection in 15 minutes after poured into the casting mold and then removed after it is cooled.