【摘要】：我國(guó)的交通運(yùn)輸業(yè)以及武器裝備業(yè)的現(xiàn)代化、高速化是主要發(fā)展方向,輕量化要求日趨強(qiáng)烈,特別是輕量化要求高的飛機(jī)、航天器、高速列車、貨運(yùn)車、汽車、火炮、坦克以及機(jī)械設(shè)備等重要受力部件和結(jié)構(gòu)件等,大量使用鋁合金鍛件和模鍛件來(lái)代替原來(lái)的鋼結(jié)構(gòu)件。普通的鋁合金生產(chǎn)方法以及傳統(tǒng)的模鍛技術(shù)難以滿足關(guān)鍵零部件的制造需求和使用性能,由于這種需求的客觀存在,使得半固態(tài)模鍛技術(shù)得到廣泛的關(guān)注。本文采用計(jì)算機(jī)模擬和實(shí)驗(yàn)相結(jié)合的方法,研究了半固態(tài)模鍛工藝參數(shù)對(duì)2024合金組織均勻性的影響。采用水淬法制備試樣,用定量金相的方法研究了半固態(tài)2024合金初生固相率與溫度的關(guān)系,繪制了初生固相率與溫度的關(guān)系曲線。應(yīng)用DEFORM-3D軟件對(duì)2024鋁合金半固態(tài)模鍛充型過(guò)程以及速度場(chǎng)進(jìn)行了模擬,研究了不同模鍛工藝參數(shù)下2024鋁合金杯形件充型過(guò)程和半固態(tài)漿料的流動(dòng)特點(diǎn)。研究表明:坯料溫度越高,充型越不平穩(wěn),速度場(chǎng)越不均勻;壓頭溫度越高,充型越平穩(wěn),速度場(chǎng)越均勻。在模擬的基礎(chǔ)上,采用實(shí)驗(yàn)的方法研究了半固態(tài)模鍛工藝參數(shù)對(duì)2024鋁合金杯形件組織均勻性的影響,研究結(jié)果表明:半固態(tài)模鍛2024合金杯形件的液相偏析度隨著合金溫度的增加而增加、隨著模具壓頭溫度的升高而減少、隨著保壓時(shí)間的延長(zhǎng)而減少、隨著充型速度的提高而增加。本實(shí)驗(yàn)條件下,在合金溫度為626℃、模具壓頭溫度為409℃、保持時(shí)間為4s、充型速度為3.5mm/s的工藝參數(shù)下,半固態(tài)模鍛2024鋁合金杯形件液相偏析度最小并且成形性較好。壓頭溫度過(guò)低會(huì)導(dǎo)致在杯形件杯口處出現(xiàn)充型不足的缺陷;在液相與固相交接處,由于兩相組織的收縮率不同易出現(xiàn)縮孔縮松應(yīng)力集中裂紋等顯微缺陷。
[Abstract]:The modernization of transportation industry and weapon equipment industry in our country, the high speed is the main development direction, the demand for lightweight is becoming stronger and stronger, especially for the aircraft, spacecraft, high-speed train, freight car, automobile and artillery, especially for the aircraft, spacecraft, high-speed train, freight car, automobile, artillery, and so on. Aluminum alloy forgings and die forgings are widely used in tank and mechanical equipment to replace the original steel structures. The common aluminum alloy production method and the traditional die forging technology can not meet the manufacturing demand and performance of key parts. Because of the objective existence of this demand, semi-solid die forging technology has been paid more and more attention. In this paper, the effect of semi-solid die forging parameters on microstructure uniformity of 2024 alloy was studied by means of computer simulation and experiment. The relationship between primary solid rate and temperature of semi-solid 2024 alloy was studied by means of quantitative metallography, and the relationship curve between primary solid rate and temperature was drawn. The filling process and velocity field of 2024 aluminum alloy semi-solid die forging were simulated by DEFORM-3D software. The filling process of 2024 aluminum alloy cup-shaped parts and the flow characteristics of semi-solid slurry under different die forging parameters were studied. The results show that the higher the billet temperature is, the more non-stationary the filling is, the more uneven the velocity field is, the higher the head temperature is, the more stable the filling is, and the more uniform the velocity field is. On the basis of simulation, the influence of semi-solid die forging process parameters on the microstructure uniformity of cup-shaped parts of 2024 aluminum alloy was studied experimentally. The results show that the liquid phase segregation of 2024 alloy cup-shaped parts in semi-solid die forging increases with the increase of alloy temperature, decreases with the increase of die head temperature, and decreases with the prolongation of holding time. With the increase of mold filling speed. Under the conditions of alloy temperature of 626 鈩，

本文編號(hào)：2465295