CN104313372A

CN104313372A - Method for preparing magnesium matrix composite semisolid slurry by adopting mechanical stirring in situ synthesis

Info

Publication number: CN104313372A
Application number: CN201410507976.8A
Authority: CN
Inventors: 闫洪; 黄文先
Original assignee: Nanchang University
Current assignee: Nanchang University
Priority date: 2014-09-29
Filing date: 2014-09-29
Publication date: 2015-01-28

Abstract

The invention relates to a method for preparing magnesium matrix composite semisolid slurry by adopting mechanical stirring in situ synthesis. The method for preparing the magnesium matrix composite semisolid slurry by adopting the mechanical stirring in situ synthesis comprises the following steps: firstly adding a Mg-Al-Zn alloy into a crucible of a smelting furnace, after the matrix alloy is molten, adding a Mg-Y intermediate alloy, regulating furnace temperature to be 850 DEG C, turning off a power supply of the smelting furnace, placing an ultrasonic amplitude transformer probe into a melt for ultrasonic treatment on the melt, standing after ultrasonic treatment is finished, and cooling to the temperature of 584-570 DEG C, and stirring the melt by adopting a mechanical stirring method, so that the Al2Y particle reinforced Mg-Al-Zn composite semisolid slurry is obtained. A covering agent is adopted and a mixed gas of SF6 and CO2 is introduced for protection in a preparation process. The prepared magnesium matrix composite semisolid slurry is uniform in structure, solid particles are small, round and normal, the semisolid rheological forming requirement of a composite can be met, a technology is simple, operation is easy, cost is low, and energy conservation and environmental protection are realized.

Description

A kind of mechanical stirring fabricated in situ prepares the method for magnesium-base composite material semi-solid state slurry

Technical field

The invention belongs to metal-base composites technical field, relate to a kind of preparation method of semisolid state slurry thereof.

Background technology

Enhancing with environmental consciousness energy-conservation along with people, magnesium alloy, as one of the lightest structural metallic materials, is more and more favored.But because magnesium alloy strength is not high, the shortcomings such as high-temperature creep resistance difference, limit its range of application.In order to improve the over-all properties of magnesium alloy, expand the Application Areas of magnesium alloy and scope, introducing wild phase, to carry out complex intensifying to magnesium alloy be an important developing direction.Utilize XD method to prepare metal-base composites, in metallic matrix, the high rigidity of one or more relatively uniform dispersions of in-situ preparation, the wild phase of high elastic coefficient, can reach the object of reinforced metal matrix.Along with the development of semi-solid state forming technique, at present, the semi-solid rheological molding technology of magnesium base composite material is combined the attention being more and more subject to numerous scholar with mechanical mixing techniques, and prepares qualified semi solid slurry and become key point for the rheological molding in later stage.By optimizing mechanical stirring processing parameter, reach promote nucleus propagation, crystal grain thinning and control solid phase particles size and roundness object.Matrix material wild phase of the present invention is Al ₂y intermetallic compound, has higher temperature of fusion (1748K), Young's modulus (158GPa), hardness (HV=645) and relatively low thermal expansivity (CTE=10 × 10 ^-6k ^-1) and density (3.93g/cm ³) etc. feature, its performance and metallographic phase seemingly, are combined with basal body interface well, comparatively adopt other wild phase as TiB ₂, TiAl ₃and Mg ₂matrix material performance in intensity and plasticity two prepared by Si etc. is all strengthened.And semi solid slurry homogeneous microstructure prepared by the present invention, solid phase particles is tiny, rounding, can meet the requirement of composite material semi-solid state rheological molding.Technique is simple, and easy to operate, cost is low, energy-conserving and environment-protective.

Summary of the invention

A kind of mechanical stirring in-situ particle is the object of the present invention is to provide to strengthen Mg-Al-Zn composite material semi-solid state slurry preparation method.

Preparation method of the present invention is: first joined by Mg-Al-Zn alloy in the crucible in smelting furnace, after matrix alloy fusing, add Mg-Y master alloy, then furnace temperature is adjusted to 850 DEG C, then turn off smelting furnace power supply, ultrasonic amplitude transformer probe is put into melt, to ultrasonic melt, leave standstill after ultrasonic stopping, cooling to 584-570 DEG C, adopt mechanical mixing method to stir melt, prepare Al ₂y particle reinforce Mg-Al-Zn composite material semi-solid state slurry.For preventing alloy oxidation, in preparation process, adopt insulating covering agent and logical SF ₆and CO ₂mixed gas is protected.

Y massfraction in Mg-Y master alloy of the present invention is 30%, and surplus is Mg; In Mg-Al-Zn alloy, the massfraction of Al is 6.0% ~ 9.2%, Zn is 0.2% ~ 0.54%, and surplus is Mg.

Insulating covering agent main component of the present invention and massfraction are: KCl is 45%, MgCl ₂be 45%, CaF ₂be 5%, BaCl ₂be 5%.

Semi solid slurry homogeneous microstructure prepared by the present invention, solid phase particles is tiny, rounding, can meet the requirement of composite material semi-solid state rheological molding, and technique is simple, and easy to operate, cost is low, energy-conserving and environment-protective.

Accompanying drawing explanation

Fig. 1 is the particle reinforce Mg-Al-Zn composite material semi-solid state slurry microstructure that under the invention process example 1 condition prepared by mechanical stirring original position.

Embodiment

The present invention will be described further by following examples.

Embodiment 1.

The present embodiment is with AZ91 alloy (Al 9.163, Zn 0.538, Mn 0.218, Si 0.042, Fe 0.0028, Cu 0.0053, Be 0.0007, Ni 0.0056, surplus is Mg, massfraction, lower same) be matrix, the Mg-Y master alloy of bulk is broken into small-particle, with aluminium-foil paper wrap be preheating to 250 DEG C stand-by.Insulation after matrix alloy fusing, add Mg-Y master alloy, again furnace temperature is adjusted to 850 DEG C, turns off smelting furnace power supply, ultrasonic amplitude transformer probe is put into melt, to ultrasonic melt, leave standstill after ultrasonic stopping, leaving standstill after ultrasonic stopping, cooling to 584 DEG C, adopt mechanical mixing method to stir melt, prepare particle reinforce Al ₂y/AZ91 magnesium-base composite material semi-solid state slurry.For preventing alloy oxidation, (main component is: KCl massfraction is 45%, MgCl to adopt insulating covering agent in preparation process ₂massfraction is 45%, CaF ₂massfraction is 5%, BaCl ₂massfraction is 5%) and logical SF ₆and CO ₂mixed gas is protected.

Embodiment 2.

The present embodiment is with AZ61 alloy (Al 6.0, Zn 0.538, Mn 0.218, Si 0.1, Fe 0.005, Cu 0.005, Ni 0.05, Others0.3, surplus is Mg, massfraction, lower same) be matrix, the Mg-Y master alloy of bulk is broken into small-particle, with aluminium-foil paper wrap be preheating to 250 DEG C stand-by.Insulation after matrix alloy fusing, add Mg-Y master alloy, again furnace temperature is adjusted to 850 DEG C, turn off smelting furnace power supply, ultrasonic amplitude transformer probe is put into melt, to ultrasonic melt, leave standstill after ultrasonic stopping, cool to 570 DEG C, adopt mechanical mixing method to stir melt, prepare particle reinforce Al ₂y/AZ61 magnesium base composite material semi solid slurry.For preventing alloy oxidation, (main component is the insulating covering agent adopted in preparation process: KCl massfraction is 45%, MgCl ₂massfraction is 45%, CaF ₂massfraction is 5%, BaCl ₂massfraction is 5%) and logical SF ₆and CO ₂mixed gas is protected.

Fig. 1 is the particle reinforce Mg-Al-Zn composite material semi-solid state slurry microstructure that under embodiment condition prepared by mechanical stirring original position.Find out from figure, semi solid slurry homogeneous microstructure prepared by the present invention, solid phase particles is tiny, rounding, can meet the requirement of composite material semi-solid state rheological molding.

Claims

1. a mechanical stirring fabricated in situ prepares the method for magnesium-base composite material semi-solid state slurry, it is characterized in that first Mg-Al-Zn alloy being joined in the crucible in smelting furnace, after matrix alloy fusing, add Mg-Y master alloy, again furnace temperature is adjusted to 850 DEG C, then turn off smelting furnace power supply, ultrasonic amplitude transformer probe is put into melt, to ultrasonic melt, leave standstill after ultrasonic stopping, cool to 584-570 DEG C, adopt mechanical mixing method to stir melt, prepare Al ₂y particle reinforce Mg-Al-Zn composite material semi-solid state slurry, adopts insulating covering agent and logical SF in preparation process ₆and CO ₂mixed gas is protected;

Y massfraction in described Mg-Y master alloy is 30%, and surplus is Mg; In Mg-Al-Zn alloy, the massfraction of Al is 6.0% ~ 9.2%, Zn is 0.2% ~ 0.54%, and surplus is Mg;

Described insulating covering agent main component and massfraction are: KCl is 45%, MgCl ₂be 45%, CaF ₂be 5%, BaCl ₂be 5%.