Microstructural development in equal-channel angular pressing using a 60° die
Microstructural development in equal-channel angular pressing using a 60° die
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DOI：
10.1016/j.actamat.2004.01.040
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发表时间：
2004-05
期刊：
影响因子：
9.4
通讯作者：
K. Furuno;Hiroki Akamatsu;K. Oh-ishi;M. Furukawa;Z. Horita;T. Langdon
中科院分区：
文献类型：
--
作者：
K. Furuno;Hiroki Akamatsu;K. Oh-ishi;M. Furukawa;Z. Horita;T. Langdon
纯铝和 Al–1%Mg–0.2%Sc 合金的坯料使用内通道角度为 60° 的模具进行等通道角挤压 (ECAP) 成功加工。对 ECAP 后的微观结构进行仔细检查，发现在宏观和微观层面上都与使用 60° 模具进行剪切的理论预测非常一致。 60° 模具引入的晶粒尺寸略小于传统 90° 模具引入的晶粒尺寸；因此，这两个模具的纯 Al 值分别为 ∼1.1 和 ∼1.2 μm，Al-Mg-Sc 合金中分别为 ∼0.30 和 ∼0.36 μm。纯铝在室温下的拉伸测试表明，使用 60° 或 90° 模具加工后，其强度相似。在 673 K 下进行的测试中，使用 60° 模具加工的 Al-Mg-Sc 合金表现出明显更高的断裂伸长率，这主要是由于该模具施加的应变较大。使用定向成像显微镜表明，Al-Mg-Sc 合金中的超塑性流动产生基本上随机的织构和边界取向错误的分布，该分布接近随机取向晶粒阵列的理论分布。
Billets of pure aluminum and an Al–1%Mg–0.2%Sc alloy were successfully processed using equal-channel angular pressing (ECAP) with a die having an internal channel angle of 60°. Careful inspection of the microstructures after ECAP revealed excellent agreement, at both the macroscopic and the microscopic levels, with the theoretical predictions for shearing using a 60° die. The grain sizes introduced with the 60° die were slightly smaller than with a conventional 90° die; thus, the values with these two dies were ∼1.1 and ∼1.2 μm in pure Al and ∼0.30 and ∼0.36 μm in the Al–Mg–Sc alloy, respectively. Tensile testing of the pure aluminum at room temperature revealed similar strengthening after processing using either a 60° or a 90° die. In tests conducted at 673 K, the Al–Mg–Sc alloy processed with the 60° die exhibited significantly higher elongations to failure due primarily to the larger strain imposed with this die. It is shown using orientation imaging microscopy that superplastic flow in the Al–Mg–Sc alloy produces an essentially random texture and a distribution of boundary misorientations that approximates to the theoretical distribution for an array of randomly oriented grains.