(1. 重慶理工大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400050；
2. 重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044)
摘 要: 為了提高AZ31鎂合金板材的力學(xué)性能，結(jié)合普通擠壓成形與大塑性剪切成形的特點(diǎn)提出了擠壓-剪切新型復(fù)合變形方式。采用DEFORM-3D軟件對(duì)板材的擠壓-剪切過程進(jìn)行數(shù)值模擬，探索塑性變形機(jī)理，研究成形過程中溫度場(chǎng)、速度場(chǎng)以及成形載荷的演變規(guī)律。結(jié)果表明：成形過程中較大溫升主要集中在剪切區(qū)域，最大溫升約為6 ℃；隨著溫度的升高，成形載荷逐漸降低，金屬的流動(dòng)速度加快，且內(nèi)部流速明顯大于外部；經(jīng)過擠壓-剪切成形后板材的晶粒得到明顯細(xì)化，并且隨著擠壓溫度的升高，晶粒逐漸長(zhǎng)大；擠壓-剪切成形使得板材表面硬度明顯升高，擠壓溫度為330 ℃、370 ℃和410 ℃時(shí)，板材的硬度分別為77 HV、75 HV、72 HV。擠壓-剪切工藝是一種新型的板材成形工藝，細(xì)化了板材的晶粒尺寸，提高了板材的力學(xué)性能。
關(guān)鍵字: 鎂合金；板材；數(shù)值模擬；熱擠壓；力學(xué)性能
（1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400050, China;
2. School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China）
Abstract:In order to improve the mechanical properties of AZ31 magnesium alloy sheet, the extrusion-shear composite deformation process was proposed by combining the characteristics of direct extrusion and continuous shearing. The extrusion-shear forming process of sheet was simulated by DEFORM-3D software. The plastic deformation mechaism was explored, and the evolution laws of temperature fields, velocity fields and forming loads during the forming process were studied. The results show that the lager temperature rise is mainly concentrated in the shearing zone during forming process, and the value of temperature rise is about 6 ℃. With the increase of temperatures, the forming load decreases gradually, and flow velocities of metal quickens, and internal flow velocities are obviously higher than those of outside. The microstructures of sheets are refined obviously after extrusion-shear forming process. With the increase of temperature, the grains grow gradually. The hardnesses of sheet surfaces prepared by extrusion-shear forming process increase obviously. When the extrusion temperatures are 330 ℃, 370 ℃ and 410 ℃, the hardnesses of the formed sheets are 77 HV, 74 HV and 72 HV, respectively. The extrusion-shear process is a new sheet forming process, which refines the grain sizes of sheets and improves the mechanical properties of sheets.
Key words: magnesium alloy; sheet; numerical simulation; extrusion-shear plate; mechanical property
