切削制备纳米材料过程的应变与温度预测

The Prediction of Strain and Temperature in the Process of Cutting for Nano-materials

大应变切削是制备纳米材料的一种新方法。切削过程中的应变和温度是影响晶粒细化程度的两个重要参数。在DEFORM软件环境下,建立铝合金6061切削过程的有限元模型,通过切削过程的有限元仿真,研究刀具的切削角度、切削用量对大应变切削过程中的材料应变、切削温度的影响规律。研究表明:影响剪切应变的主要因素是刀具前角,前角越小,对应的剪切应变越大;大应变主要集中在剪切区域,即第一变形区;影响切削温度的主要因素是切削速度,在切削速度较低时,切削温度上升速度缓慢,将切削速度由目前20mm/s提高到100mm/s,仍然可以使切削温度控制在铝合金6061动态再结晶温度之下,可以大幅度提高制备纳米材料的效率。

Large stain deformation by machining is a new method of preparing nanostructured materials. Strain and temperature in the cutting process are the two important parameters which impact the grain refinement. In the DEFORM software environment, the finite element model of 6061 aluminum alloy cutting process was established. Through the finite element simulation of the cutting process, the regularities of strain and temperature, which influenced by the angle of tool and cutting parameters were revealed in the cutting process. Study shows that： the main factor impacting the shear strain is rake angle. The smaller the rake angle, the bigger of the shear strain. The large strain mainly concentrate in the shear region, which is the first deformation zone. The main impacting factor on cutting temperature is cutting speed, and the cutting temperature rises slowly in the low cutting speed. When the cutting speed rises from 20 mm/s to 100 mm/s, the temperature can be still controlled under the dynamic recrystallization temperature of 6061 aluminum alloy, and it can improve the efficiency of preparation of nanomaterials.