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

Abstract

The present invention provides a high-plasticity composite modified aluminum alloy product and a preparation method therefor. Wherein, the preparation method includes the following steps: step S1, providing an aluminum alloy melt; step S2, providing a modifier; step S3, adding the modifier to the aluminum alloy melt under an inert gas atmosphere and melting, to obtain a modified aluminum alloy melt; step S4, performing casting by using the modified aluminum alloy melt, to obtain the cast aluminum alloy blank; and step S5, performing a heat treatment on the modified aluminum alloy blank, wherein, the heat treatment includes: a solution treatment, involving heating the aluminum alloy blank to 530° C.-550ºC, and maintaining the temperature for 120-300 min; a water quenching treatment, involving adding the aluminum alloy blank after the solution treatment into a water bath with the temperature of 60° C.-70° ° C., and water quenching same for 2-4 min; an aging treatment, involving maintaining the aluminum alloy blank after the water quenching treatment at 110° C.-140° ° C. for 120-240 min, then further raising the temperature to 160° C.-200° C. and maintaining the temperature for 20-60 min, and then cooling to room temperature to obtain the high-plasticity composite modified aluminum alloy part.

1 . A method for preparing a high-plasticity composite modified aluminum alloy part, comprising the following steps:
 step S1, providing an aluminum alloy melt:   step S2, providing a modifier: wherein   the modifier is a combination of a composite rare earth aluminum alloy and an aluminum-titanium master alloy or a composite rare earth aluminum alloy and an aluminum-titanium-boron master alloy, and the composite rare earth aluminum alloy contains strontium, titanium or titanium and boron, and a rare earth metal, the mass ratio of the total amount of the rare earth metal: strontium: titanium or titanium and boron is 1:(0.1-1.2): (0.1-1.2), and the rare earth metal in the composite rare earth aluminum alloy is any one or more of lanthanum and cerium, and yttrium, the preparation of the composite rare earth aluminum alloy comprises:   step S211, providing an aluminum melt:   step S212, 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 S213, 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:   step S3, adding the modifier to the aluminum alloy melt under an inert gas atmosphere and melting, to obtain a modified aluminum alloy melt, wherein the modifier accounts for 0.4-0.6 wt % of the total amount of the modified aluminum alloy melt:   step S4, performing casting by using the modified aluminum alloy melt, to obtain a modified aluminum alloy blank:   step S5, performing a heat treatment on the modified aluminum alloy blank, wherein the heat treatment comprises:   a solution treatment, involving heating the modified aluminum alloy blank to 530-550° ° C., and holding for 120-300 min:   a water quenching treatment, involving 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, involving holding the aluminum alloy blank after the water quenching treatment at 110-140° ° C. for 120-240 min, then further raising the temperature to 160-200° C. and holding for 20-60 minutes, and raising the temperature from 110-140° ° C. to 160-200° C. at a heating rate of 2-4° C./min, and then cooling to room temperature, to obtain the high-plasticity composite modification alloy part.   
     
     
         2 . The preparation method according to  claim 1 , wherein the step S1 comprises:
 providing an aluminum alloy ingot:   removing an oxide scale layer on a surface of the aluminum alloy ingot, cleaning, and drying:   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 step S3 comprises:
 step S310, adding the composite rare earth aluminum alloy into the aluminum alloy melt and melting, to obtain a fourth uniformly mixed melt; and   step S320, 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.   
     
     
         4 . The preparation method according to  claim 1 , wherein in the step S5, the heating rate in the solution treatment is controlled at 1.5-3° C./min, and the holding time is controlled within 120-180 min. 
     
     
         5 . 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.   
     
     
         6 . A high-plasticity composite modified aluminum alloy part,
 wherein the high-plasticity composite modified aluminum alloy part is obtained by the preparation method according to  claim 1 , and a tensile strength of the high-plasticity composite modified aluminum alloy part is 280 MPa or more, a yield strength is 200 MPa or more, and an elongation rate is 12% or more.