Sc微合金化纯铝大变形组织与强化机制

发布时间：2018-01-26 06:05

本文关键词： 大变形组织演变强化机制钪微合金化　出处：《稀有金属》2017年08期 　论文类型：期刊论文

【摘要】：以工业纯铝和Al-1%Sc合金为原料,通过熔炼得到Sc微合金化纯铝(Al-0.1%Sc)。采用X射线衍射(XRD)分析、电子背散射衍射(EBSD)分析技术以及拉伸实验,研究了Al-0.1%Sc合金在等通道转角挤压(ECAP)和压缩大应变加工过程中的组织演变和强化机制。ECAP试验采用工艺路线Bc进行3道次挤压加工,即每次挤压后将工件沿轴线方向旋转90°,旋转方向不变,挤压速度为5 mm·s-1。结果表明:ECAP加工使得合金平均晶粒尺寸减小,晶粒尺寸基本被细化到4 mm以下;显著提高了合金强度,抗拉强度由105 MPa提高到162 MPa;降低了合金中低角度晶界比例,从0.889减小到0.652;使得合金内部积累了一定量的位错,位错密度为0.5321014 m-2。而后续的压缩大应变加工对合金的平均晶粒尺寸几乎没有影响,使得合金的抗拉强度提高到176 MPa,使得合金的低角度晶界比例提高到0.765,使得合金的位错密度提高到1.7151014 m-2。大应变Al-0.1%Sc合金的强化主要由晶格摩擦应力、位错强化、低角度晶界强化和高角度晶界强化组成,其中低角度晶界和位错的强化贡献占绝大部分。
[Abstract]:With industrial pure aluminum and Al-1%Sc alloy as raw material, obtained by melting Sc micro alloying of pure aluminum (Al-0.1%Sc). By using X ray diffraction (XRD) analysis, electron backscatter diffraction (EBSD) analysis and tensile test of Al-0.1%Sc alloy in equal channel angular extrusion (ECAP) evolution and strengthening mechanism of.ECAP experiment Bc compression process and large strain in the process of 3 passes extrusion, namely each compression after the workpiece rotation along the axial direction of 90 degrees, the direction of rotation invariant, the extrusion speed is 5 mm - s-1. results showed that ECAP processing the average grain size of alloy decreases, the grain size is refined to 4 mm the following; improve the strength of the alloy, the tensile strength increased from 105 MPa to 162 MPa; reduce the proportion of alloy of low angle grain decreased from 0.889 to 0.652; the dislocation makes the alloy internal accumulation of a certain amount, the dislocation density is 0.5321 014 m-2. and compression of large strain processing subsequent average grain size of the alloy is almost no effect, the tensile strength of the alloy increases to 176 MPa, the alloy with low angle grain boundaries increased to 0.765, the dislocation density increased to 1.7151014 m-2. alloy strengthening large strain of Al-0.1%Sc alloy is mainly composed of lattice friction stress, dislocation strengthening low angle grain boundary strengthening, and the high angle grain boundary strengthening, strengthening the contribution of low angle grain boundaries and dislocations of the majority.

【作者单位】：江苏大学先进制造与现代装备技术工程研究院;
【基金】：国家自然科学资金项目(51074079) 江苏省高校科研成果产业化推进项目(JH10-37) 江苏大学“拔尖人才培养工程”基金项目(1211110001)资助
【分类号】：TG146.21
【正文快照】： 微观组织结构是影响金属材料力学性能一个非常重要的因素。在铝合金中加入微量钪(Sc)可以显著改善其微观组织,从而提高合金的强度[1]。研究微观组织结构与力学性能之间的联系,尤其是通过数学建模,在利用公式精确计算的前提下定量阐明其影响关系,已经逐渐地成为材料科学十分重

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