(1. 哈爾濱理工大學(xué) 材料科學(xué)與工程學(xué)院，哈爾濱 150040；
2. 哈爾濱吉星機(jī)械工程有限公司，哈爾濱 150069；
3. 東京大學(xué) 生產(chǎn)技術(shù)研究所，東京153-8505)
摘 要: 以ADC12鋁合金為原料，采用近液相線(xiàn)擠壓鑄造生產(chǎn)汽車(chē)鋁合金支架，研究近液相線(xiàn)擠壓鑄造技術(shù)工藝參數(shù)對(duì)汽車(chē)承力件鋁合金支架組織及力學(xué)性能的影響。結(jié)果表明：近液相線(xiàn)擠壓鑄造可獲得均勻細(xì)小的球狀組織。在595到 625 ℃的澆注溫度范圍內(nèi)，球狀組織逐漸長(zhǎng)大為薔薇狀晶及樹(shù)枝晶，球狀系數(shù)降低，晶粒尺寸升高，抗拉強(qiáng)度及伸長(zhǎng)率均有所降低。在斷口分析中，韌窩的數(shù)量減少，解理面的數(shù)量增多；隨著壓強(qiáng)由90 MPa上升到180 MPa，球狀晶生長(zhǎng)時(shí)間逐漸減少，最后以球狀晶形式存在，球狀系數(shù)升高，晶粒尺寸減小，抗拉強(qiáng)度及伸長(zhǎng)率逐漸升高；隨著保壓時(shí)間從10 s延長(zhǎng)到25 s，抗拉強(qiáng)度及伸長(zhǎng)率有所增加。近液相線(xiàn)擠壓鑄造的最佳工藝為：澆注溫度為605 ℃、壓力為150 MPa、保壓時(shí)間為20 s。由于鋁液的流動(dòng)，球狀晶長(zhǎng)大成孿生的薔薇狀晶。
關(guān)鍵字: 近液相線(xiàn)擠壓鑄造；ADC12鋁合金；鋁合金支架；球狀組織；力學(xué)性能
（1. School of Material Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China;
2. Harbin Jixing Mechanical Engineering Limited Company, Harbin 150040, China;
3. Institute of Industry Science, the University of Tokyo, Tokyo 153-8505, Japan）
Abstract:The effect of near liquidus squeeze casting (NLSC) process on microstructure and mechanical properties of ADC12 alloy differential support was investigated. The results show that uniform globular crystals are obtained by NLSC. With the pouring temperature increasing from 595 to 625 ℃, the globular crystals grow into rosette crystals or dendrites, the average globular coefficient (AGC) decreases and the average grain size (AGS) increases, leading to a reduction of tensile strength and elongation. The dimple quantity decreases, meanwhile, the quantities and areas of cleavage planes increases in fracture appearance. With the increase of pressure from 90 to 180 MPa, AGC increases and AGS decreases, leading to an increase of tensile strength and elongation. As the holding time increases from 10 to 25 s, the tensile strength and elongation increase slightly. The optimal parameters of NLSC process are pouring temperature of 605 ℃, pressure of 150 MPa and holding time of 20 s. The globular crystals grow to the twin rosette crystals easily due to the flow of metal.
Key words: near-liquidus squeeze casting; ADC12 aluminium alloy; aluminium differential support; globular crystal; mechanical property
