High-strength composite modified aluminum alloy part and preparation method therefor

Abstract

The present invention provides a high-strength composite modified aluminum alloy part and a preparation method therefor. The preparation method includes: providing an aluminum alloy melt; providing a modifier; adding the modifier to the aluminum alloy melt under an inert gas atmosphere and melting, to obtain a modified aluminum alloy melt; performing casting by using the modified aluminum alloy melt, to obtain the cast aluminum alloy blank; and performing a heat treatment on the modified aluminum alloy blank, wherein the heat treatment includes: a solution treatment, a water quenching treatment, and an aging treatment.

1 . A method for preparing a high-strength composite modified aluminum alloy part, comprising the following steps:
 step S 1 , providing an aluminum alloy melt;   step S 2 , providing a modifier; wherein   the modifier is a combination of a rare earth aluminum alloy, an aluminum-strontium master alloy, and an aluminum-titanium or aluminum-titanium-boron master alloy, or   the modifier is a combination of a composite rare earth aluminum alloy and an aluminum-titanium or aluminum-titanium-boron master alloy, and the composite rare earth aluminum alloy contains strontium, titanium or titanium boron, and a rare earth metal, and   the rare earth metal in the rare earth aluminum alloy and the composite rare earth aluminum alloy is any one or more of lanthanum, cerium, and yttrium;   step S 3 , adding the modifier to the aluminum alloy melt under an inert gas atmosphere and melting, to obtain a modified aluminum alloy melt;   step S 4 , performing casting by using the modified aluminum alloy melt, to obtain a modified aluminum alloy blank; and   step S 5 , performing a heat treatment on the modified aluminum alloy blank, wherein the heat treatment comprises:   a solution treatment, heating the modified aluminum alloy blank to 530-550° C., and holding for 100-300 min;   a water quenching treatment, adding the modified aluminum alloy blank after the solution treatment into a water bath at a temperature of 60-70° C., and quenching with water for 2-4 min; and   an aging treatment, holding the modified aluminum alloy blank after the water quenching treatment at 150-165° C. for 120-280 min, then further cooling to 110-130° C. and holding for 30-120 min, and then naturally cooling to room temperature, to obtain the high-strength composite modification alloy part.   
     
     
         2 . The preparation method according to  claim 1 , wherein the step S 1  comprises:
 providing an aluminum alloy ingot; 
 removing an oxide scale layer on a surface of the aluminum alloy ingot, cleaning, and drying; and 
 melting the dried aluminum alloy ingot, refining, and removing slag, to obtain the aluminum alloy melt, wherein 
 the composition of the aluminum alloy ingot is a hypoeutectic aluminum alloy or a eutectic aluminum alloy. 
 
     
     
         3 . The preparation method according to  claim 1 , wherein the modifier is a combination of a rare earth aluminum alloy, an aluminum-strontium master alloy, and an aluminum-titanium or aluminum-titanium-boron master alloy, wherein the aluminum-strontium master alloy and the aluminum-titanium or aluminum-titanium-boron master alloy are added at intervals, and
 the rare earth aluminum alloy is added first, or added together with the first added component, or added at an interval between adding the aluminum-strontium master alloy and adding the aluminum-titanium or aluminum-titanium-boron master alloy.   
     
     
         4 . The preparation method according to  claim 3 , wherein the step S 3  comprises:
 step S 301 , adding the rare earth aluminum alloy into the aluminum alloy melt and melting, to obtain a first homogeneously mixed melt; 
 step S 302 , adding the aluminum-strontium master alloy into the first homogeneously mixed melt and continuing melting, to obtain a second homogeneously mixed melt; and 
 step S 303 , adding the aluminum-titanium or aluminum-titanium-boron master alloy into the second homogeneously mixed melt and continuing melting, to obtain the modified aluminum alloy. 
 
     
     
         5 . The preparation method according to  claim 1 , wherein the modifier is a combination of a composite rare earth aluminum alloy and an aluminum-titanium or aluminum-titanium-boron master alloy, and the step S 3  comprises:
 step S 310 , adding the composite rare earth aluminum alloy into the aluminum alloy melt and melting, to obtain a fourth homogeneously mixed melt; and 
 step S 320 , adding the aluminum-titanium or aluminum-titanium-boron master alloy into the fourth homogeneously mixed melt and continuing melting, to obtain the modified aluminum alloy. 
 
     
     
         6 . The preparation method according to  claim 5 , wherein the preparation of the composite rare earth aluminum alloy comprises:
 step S 211 , providing the aluminum melt;   step S 212 , providing an aluminum-strontium master alloy, an aluminum-titanium or aluminum-titanium-boron master alloy, and a rare earth aluminum master alloy, wherein the rare earth metal in the rare earth aluminum master alloy is one or more selected from lanthanum, cerium, and yttrium; and   step S 213 , under an inert gas atmosphere, sequentially adding the rare earth aluminum alloy, the aluminum-strontium master alloy, and the aluminum-titanium or aluminum-titanium-boron master alloy into the aluminum melt and melting, to obtain the composite rare earth aluminum alloy.   
     
     
         7 . The preparation method according to  claim 1 , wherein the modifier accounts for 0.4-0.6 wt % of the total amount of the modified aluminum alloy melt, and the mass ratio of the total amount of the rare earth metal:strontium:titanium or titanium boron is 1:(0.1-1.2):(0.1-1.2). 
     
     
         8 . The preparation method according to  claim 1 , wherein in the step S 5 , a heating rate in the solution treatment is controlled at 1.5-3° C./min, and the holding time is controlled within 120-180 min. 
     
     
         9 . The preparation method according to  claim 1 , wherein the solution treatment, the water quenching treatment, and the aging treatment are continuous treatments, and the water bath is a circulating water bath, and after the water quenching treatment, before the aging treatment is performed, the temperature of the cast aluminum alloy blank is kept above 55° C. 
     
     
         10 . The preparation method according to  claim 1 , wherein in the aging treatment stage, the temperature is cooled from 150-165° C. to 110-130° C. at a cooling rate of 2-5° C./min. 
     
     
         11 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 1 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         12 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 2 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         13 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 3 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         14 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 4 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         15 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 5 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         16 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 6 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         17 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 7 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         18 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 8 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         19 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 9 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more. 
     
     
         20 . A high-strength composite modified aluminum alloy part, wherein the high-strength composite modified aluminum alloy part is obtained by the preparation method according  claim 10 , a tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, a yield strength is 230 MPa or more, and an elongation rate is 6% or more.