(華南理工大學 國家金屬材料近凈成形工程技術中心，廣州 510640)
摘 要: 為了系統(tǒng)研究半固態(tài)7050鋁合金的觸變力學行為，采用Gleeble-3500熱模擬試驗機對SIMA法制備的半固態(tài)7050鋁合金進行單向壓縮試驗，利用SPPS數(shù)理統(tǒng)計軟件擬合材料本構模型，最后通過MSC.MARC軟件進行半固態(tài)軋制過程的數(shù)值模擬。結果表明：7050鋁合金的壓縮流變應力與溫度、應變速率以及應變具有相關性，在0.1~10 s-1的應變速率范圍內，流變應力隨溫度的升高而明顯降低，隨應變速率和變形量的增大而增大；利用壓縮試驗測得真應力—真應變關系，可以建立半固態(tài)7050鋁合金分階段觸變變形的粘塑性本構模型，該模型基于半固態(tài)材料的力學特性，并考慮液相分數(shù)的影響；模擬計算得到的穩(wěn)態(tài)軋制力約為25 MPa，與實際軋制實驗結果基本吻合，證明所建立的本構模型是合理的。
關鍵字: 半固態(tài)；熱模擬；本構方程；軋制
（National Engineering Research Center of Near-net-shape Forming Technology for Metallic Materials,
South China University of Technology, Guangzhou 510640, China）
Abstract:In order to investigate the thixo-forming deformational behavior of 7050 aluminum alloy systematically, the semi-solid material prepared by SIMA method was studied on the Gleeble-3500 material thermo-simulation machine via uniaxial compression tests. The viscoplastic model of flow stress at semi-solid temperature was established by using SPSS software. At last, the rolling process was simulated by MSC.MARC finite element software. The results show that, the compression flow stress of 7050 aluminum alloy has a close relationship with temperature, strain rate and strain. In the strain range from 0.1 s-1 to 10 s-1, the flow stress decreases significantly with the temperature increasing and rises considerably with the strain and strain rate increasing. The two-stage viscoplastic model of flow stress is established by using the obtained true strain—true strain rate curves, which considers the mechanical properties of semi-solid state material and liquid fractions. The simulation results show the stable rolling force is around 25 MPa, which agrees with experimental results. So, the established constitutive equations are reasonable.
Key words: semi-solid; thermo-simulation; constitutive equations; rolling
