Aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for 5g base station and preparation method thereof

Abstract

An AMC, and in particular to an AMC with high strength, high toughness, high thermal conductivity, and good weldability for a 5G base station and a preparation method thereof. A strip of the AMC with high strength, high toughness, high thermal conductivity, and good weldability for a 5G base station can be prepared by an electromagnetically and ultrasonically-controlled twin-roll continuous casting device developed and designed based on chemical composition designing, in-situ nanoparticle strengthening and refinement, and REM microalloying. The composite strip prepared by this technology has fine grains, nano-REM precipitated phases in grains, and in-situ nano-ceramic particles with high thermal conductivity at grain boundaries, which significantly improves strength, toughness, and thermal conductivity of the alloy at room temperature, and increases a grain boundary content and effectively improves roll cold weldability of the alloy strip since the alloy composition design with a low melting point and the significant grain refinement.

1 . An aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for a 5G base station, prepared by an electromagnetically and ultrasonically-controlled twin-roll continuous casting-rolling device based on chemical composition designing, in-situ nanoparticle strengthening and refinement, and rare-earth metal microalloying, to obtain a cast-rolled strip of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station, wherein the cast-rolled strip of the aluminum matrix composite comprises the following components in mass percentage: Si: 1.0 to 1.5, Fe: 0.6 to 1.0, Cu: 0.05 to 0.2, Mn: 1.0 to 2.0, Zr: 0.5 to 1.0, Ti: 0.5 to 1.0, B: 0.5 to 2.0, O: 0.2 to 1.0, Er: 0.05 to 0.3, Sc: 0.05 to 0.3, Y: 0.1 to 0.5, Zn: less than or equal to 0.5, Mg: less than or equal to 0.5, Cr: less than or equal to 0.5, and Al: the balance; the chemical composition designing comprises: on a basis of a 3003 aluminum alloy, increasing a content of Si to 1.0 wt. % to 1.5 wt. % to further reduce a melting point of the alloy, and adding Zr, Ti, B, O, Er, Sc, and Y to the alloy to allow the in-situ nanoparticle strengthening and refinement, the rare-earth metal microalloying, and matrix grain refinement, and improve strength, toughness, and ply-roll weldability of the alloy; the cast-rolled strip of the aluminum matrix composite has a grain size of less than or equal to 60 μm, a tensile strength of more than or equal to 250 MPa, a yield strength of more than or equal to 120 MPa, and an elongation rate of more than or equal to 20%; the cast-rolled strip of the aluminum matrix composite has a thermal conductivity of higher than or equal to 250 W/(m*K), which is 30% or more higher than 190 W/(m*K) of the 3003 aluminum alloy; and a ply-roll welding temperature of the cast-rolled strip of the aluminum matrix composite is lower than or equal to 500° C. 
     
     
         2 . (canceled) 
     
     
         3 . The aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 1 , wherein the in-situ nanoparticle strengthening and refinement comprises: producing nano-ZrB 2 , Al 2 O 3 , and TiB 2  ceramic particles with high hardness, high thermal conductivity, and low expansibility through a reaction of an in-situ reactive powder with an Al melt, wherein the nano-ceramic particles serve as heterogeneous nucleation cores of α-Al to significantly refine matrix grains, and are finally distributed in grains or at grain boundaries to improve strength and toughness of the composite through an interaction with dislocations; the nano-ceramic particles synthesized in-situ efficiently refine the matrix grains, significantly increase a grain boundary content, and reduce a ply-roll cold welding temperature; the in-situ nanoparticles have a particle size of 10 nm to 100 nm, and a content of the in-situ nanoparticles is 1% to 15% of a volume of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability; and the in-situ reactive powder is two to more selected from the group consisting of Co 3 O 4 , K 2 ZrF 6 , K 2 TiF 6 , KBF 4 , Na 2 B 4 O 7 , ZrO 2 , B 2 O 3 , and Al 2 (SO 4 ) 3 . 
     
     
         4 . The aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 1 , wherein the rare-earth metal microalloying comprises: composite addition of rare-earth metals Sc, Er, and Y to the composite, such that the rare-earth metals react with Al and Zr to produce nano-Al 3 Er, Al 3 Sc, Al 3 (Er+Zr), Al 3 (Sc+Zr), and Al 3 Y rare-earth metal precipitated phases dispersed in matrix grains, to significantly improve a strength and a work hardening capacity of the composite and enable an excellent ductility; and the addition of the rare-earth metals also purifies a melt, eliminate inclusions in pores, improve wettability of in-situ nano-ceramic particles, promote spheroidization of the in-situ nano-ceramic particles, and allow strengthening and toughening of the in-situ nano-ceramic particles and the rare-earth metals in a synergetic and coupled manner. 
     
     
         5 . A preparation method of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 1 , wherein the aluminum matrix composite is prepared by the electromagnetically and ultrasonically-controlled twin-roll continuous casting-rolling device, and the preparation method comprises the following specific steps:
 (1) blowing an in-situ reactive powder uniformly into an aluminum melt through a gas flow channel of a degassing system;   (2) in-situ synthesizing nano-ceramic particles under non-contact stirring of a helical magnetic field;   (3) adding rare-earth metal intermediate alloys, uniformly compounding to obtain a composite melt, and subjecting the composite melt to a high-energy ultrasonic treatment to improve uniform distribution of in-situ nano-ceramic particles and rare-earth metals in the composite melt; and   (4) casting-rolling the composite melt to obtain the cast-rolled strip of the composite.   
     
     
         6 . The preparation method of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 5 , wherein the electromagnetically and ultrasonically-controlled twin-roll continuous casting-rolling device comprises the helical magnetic field, the degassing system, a filtration system, a liquid level control launder, a high-energy ultrasonic generator, a casting nozzle, a casting-rolling machine, and a strip winder, wherein the helical magnetic field is arranged around a melting pool of the degassing system and is configured to allow non-contact helical electromagnetic stirring for a melt; the degassing system comprises the melting pool and a hollow blowing rotor and is configured to degas the melt and blow the in-situ reactive powder into the melt; the degassing system communicates with the filtration system, and the filtration system communicates with the liquid level control launder; the high-energy ultrasonic generator is arranged in the liquid level control launder at a front end of the casting nozzle and is configured to promote uniform dispersion of an in-situ nano-strengthening substance and homogenization of melt components; and the casting-rolling machine and the strip winder are sequentially arranged at a rear end of the casting nozzle. 
     
     
         7 . The preparation method of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 6 , wherein a ceramic filter screen is provided in the filtration system; and a shearing machine is provided at a rear end of the casting-rolling machine, and a spraying system is provided at a side of the casting-rolling machine. 
     
     
         8 . The preparation method of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 5 , wherein in the step (1), an Ar gas with a purity of 99.99% is adopted for degassing, and the hollow blowing rotor has a rotational speed of 300 r/min to 400 r/min; in the step (2), an in-situ reaction is conducted at 850° ° C. to 900° ° C. for 20 min to 30 min, and the helical magnetic field has a frequency of 15 Hz to 30 Hz and an intensity of 0.3 T to 0.5 T; and in the step (3), the rare-earth metal intermediate alloys are added in forms of Al-20Er, Al-5Sc, and Al-10Y, and the high-energy ultrasonic treatment is conducted with an ultrasonic power of 5 kW to 10 KW and in an ultrasonic mode of continuous ultrasound. 
     
     
         9 . The preparation method of the aluminum matrix composite with high strength, high toughness, high thermal conductivity, and good weldability for the 5G base station according to  claim 5 , wherein in the step (4), a temperature of the composite melt in the casting nozzle is maintained at 700° C. to 720° C.