Effect of ball milling on the ageing response of Al2618 composites reinforced with SiC and oxide nanoparticles
Effect of ball milling on the ageing response of Al2618 composites reinforced with SiC and oxide nanoparticles
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DOI：
10.1016/j.jallcom.2016.09.265
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发表时间：
2017-02
影响因子：
6.2
通讯作者：
R. Casati;J. Fiocchi;A. Fabrizi;N. Lecis;F. Bonollo;M. Vedani
中科院分区：
文献类型：
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作者：
R. Casati;J. Fiocchi;A. Fabrizi;N. Lecis;F. Bonollo;M. Vedani
采用高能球磨法在Al 2618合金基体中分散SiC纳米颗粒（非原位增强体）和氧化物碎片（原位增强体）。纳米复合材料粉末通过在600 °C下热乳来固结。使用球磨粉末生产的样品显示出较弱的响应，老化处理所证明的热和显微组织分析和硬度测试。球磨引起的粉末的反复塑性变形导致高密度的晶体缺陷，这被认为是负责的固溶度的扩展，从而降低了老化过程中沉淀的驱动力。在室温和120 °C下对溶液处理和峰值老化的样品进行拉伸测试。纳米复合材料表现出显着的高屈服强度和令人印象深刻的能力，即使在高温下保持高的机械性能。时效前后的应力-应变曲线均出现明显的锯齿状，这是动态应变时效机制的结果。
High-energy ball milling was carried out to disperse SiC nanoparticles (ex-situ reinforcement) and fragments of oxide (in-situ reinforcement) in an Al2618 alloy matrix. Nanocomposite powders were consolidated by hot rolling at 600 °C. Samples produced using ball milled powder showed a weak response to ageing treatment as demonstrated by thermal and microstructural analyses and by hardness tests. Repeated plastic deformation of powder induced by ball milling led to high density of crystal defects which are believed to be responsible of an extension of solid solubility, thus reducing the driving force for precipitation during ageing. Tensile tests were performed at room temperature and at 120 °C on solution treated and peak-aged samples. The nanocomposites showed a remarkably high yield strength and an impressive ability in keeping high mechanical properties even at high temperature. Serrations were noticeable in stress-strain curves both before and after ageing, which are ascribed to the dynamic strain ageing mechanism.