Strengthening mechanisms in a high-strength bulk nanostructured Cu-Zn-Al alloy processed via cryomilling and spark plasma sintering
Strengthening mechanisms in a high-strength bulk nanostructured Cu-Zn-Al alloy processed via cryomilling and spark plasma sintering
复制标题
DOI：
10.1016/j.actamat.2012.09.036
复制
发表时间：
2013-05-01
期刊：
影响因子：
9.4
通讯作者：
Lavernia, Enrique J.
中科院分区：
文献类型：
--
作者：
Wen, Haiming;Topping, Troy D.;Lavernia, Enrique J.
一种标称成分为Cu-30 Zn-0.8Al wt.%的块状纳米结构合金，通过黄铜粉末的低温研磨和随后的低温研磨粉末的放电等离子体烧结（SPS）来制造黄铜260合金（商业名称为黄铜260），产生950 MPa的压缩屈服强度，其显著高于商业黄铜260合金的屈服强度（类似于200-400 MPa）。透射电子显微镜的研究表明，低温球磨的结果在26纳米的平均晶粒直径和高密度的变形孪晶。低温球磨粉末SPS后获得了几乎完全致密的块状样品，平均粒径为110 nm。SPS后，10体积%孪晶的平均厚度为30 nm。三维原子探针层析成像研究表明，烧结体中Al的分布非常不均匀，基体中存在Al（Cu，Zn）-O-N、Al-O-N和Al-N等含Al析出相。沉淀物的平均直径为1.7 nm，体积分数为0.39%。定量计算了烧结体样品中不同强化贡献，包括晶界、孪晶界、沉淀、位错和固溶强化。从分析结果表明，沉淀和晶界强化是占主导地位的强化机制，和计算的总屈服强度是在合理的协议与实验确定的压缩屈服强度。(c)2012 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
A bulk nanostructured alloy with the nominal composition Cu-30Zn-0.8Al wt.% (commercial designation brass 260) was fabricated by cryomilling of brass powders and subsequent spark plasma sintering (SPS) of the cryomilled powders, yielding a compressive yield strength of 950 MPa, which is significantly higher than the yield strength of commercial brass 260 alloys (similar to 200-400 MPa). Transmission electron microscopy investigations revealed that cryomilling results in an average grain diameter of 26 nm and a high density of deformation twins. Nearly fully dense bulk samples were obtained after SPS of cryomilled powders, with average grain diameter 110 nm. After SPS, 10 vol.% of twins is retained with average twin thickness 30 nm. Three-dimensional atom-probe tomography studies demonstrate that the distribution of Al is highly inhomogeneous in the sintered bulk samples, and Al-containing precipitates including Al(Cu,Zn)-O-N, Al-O-N and Al-N are distributed in the matrix. The precipitates have an average diameter of 1.7 nm and a volume fraction of 0.39%. Quantitative calculations were performed for different strengthening contributions in the sintered bulk samples, including grain boundary, twin boundary, precipitate, dislocation and solid-solution strengthening. Results from the analyses demonstrate that precipitate and grain boundary strengthening are the dominant strengthening mechanisms, and the calculated overall yield strength is in reasonable agreement with the experimentally determined compressive yield strength. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.