Effect of acute tool-angles on equal channel angular extrusion/pressing
Effect of acute tool-angles on equal channel angular extrusion/pressing
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DOI：
10.1016/j.msea.2005.08.043
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发表时间：
2005-11
期刊：
影响因子：
6.4
通讯作者：
A. Nagasekhar;Y. Tick-Hon;Sean Li;H. P. Seow
中科院分区：
文献类型：
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作者：
A. Nagasekhar;Y. Tick-Hon;Sean Li;H. P. Seow
在等通道转角挤压（ECAE）中，锐角工具角可以在最小道次内增加材料中诱导的应变。这种增加的应变可以产生超细晶粒和高比例的大角度晶界，这增强了机械和超塑性性能。但对变形量和凸模压力的要求将更加严格，要求细致。在这项研究中，与90°相比，使用Abaqus/Explicit对60°和75°的模具/通道角度进行ECAE有限元模拟。所有模拟均考虑10°的外角角。模拟中考虑了材料的应变硬化和摩擦等实际现象。当通道锐角θ =60°和75°时，变形分三步进行，当通道锐角θ = 90°时，变形分两步进行。角部间隙通常是90°通道角情况下的主要缺点，但不是锐角通道角的因素。冲头压力的要求也被发现是高与尖锐的工具角度。
Acute tool-angles in equal channel angular extrusion (ECAE) can increase the strain induced in the material within minimum number of passes. Such increased strains can yield ultrafine grains and high fraction of high angle grain boundaries, which enhance mechanical and superplastic properties. However, the deformation and punch pressure requirements will be more stringent demanding detailed investigation. In this study, finite element simulations of ECAE were carried with Abaqus/Explicit for die/channel angles of 60° and 75° in comparison to 90°. Outer corner angle of 10° was considered for all simulations. Factual phenomena like strain hardening of material and friction were considered for the simulations. Deformation was found to take place in three steps for acute channel angles ϕ=60° and 75°, two steps for that of 90°. Corner gap, which is often the major drawback in the case of 90° channel angle, was not a factor for the acute channel angles. Punch pressure requirements were also found to be high with acute tool-angles.