Rosalie Julian M, Guo Jinming, Pippan Reinhard, Zhang Zaoli
Erich Schmid Institute, Austrian Academy of Sciences, Jahnstrasse 12, 8700 Leoben, Austria.
J Mater Sci. 2017;52(16):9872-9883. doi: 10.1007/s10853-017-1142-2. Epub 2017 May 9.
Nanostructured molybdenum-copper composites have been produced through severe plastic deformation of liquid-metal infiltrated Cu30Mo70 and Cu50Mo50 (wt%) starting materials. Processing was carried out using high-pressure torsion at room temperature with no subsequent sintering treatment, producing a porosity-free, ultrafine-grained composite. Extensive deformation of the Cu50Mo50 composite via two-step high-pressure torsion produced equiaxed nanoscale grains of Mo and Cu with a grain size of 10-15 nm. Identical treatment of Cu30Mo70 produced a ultrafine, lamellar structure, comprised of Cu and Mo layers with thicknesses of and , respectively, and an interlamellar spacing of 9 nm. This microstructure differs substantially from that of HPT-deformed Cu-Cr and Cu-W composites, in which the lamellar microstructure breaks down at high strains. The ultrafine-grained structure and absence of porosity resulted in composites with Vickers hardness values of 600 for Cu30Mo70 and 475 for Cu50Mo50. The ability to produce Cu30Mo70 nanocomposites with a combination of high-strength, and a fine, oriented microstructure should be of interest for thermoelectric applications.
通过对液态金属渗入的Cu30Mo70和Cu50Mo50（重量百分比）起始材料进行严重塑性变形，制备出了纳米结构的钼铜复合材料。加工过程在室温下采用高压扭转进行，且无需后续烧结处理，从而制得无孔隙的超细晶粒复合材料。通过两步高压扭转对Cu50Mo50复合材料进行广泛变形，得到了尺寸为10 - 15纳米的等轴纳米级钼和铜晶粒。对Cu30Mo70进行相同处理后，得到了一种超细的层状结构，由厚度分别为[此处原文缺失厚度具体数值]和[此处原文缺失厚度具体数值]的铜层和钼层组成，层间距为9纳米。这种微观结构与高压扭转变形的Cu - Cr和Cu - W复合材料的微观结构有很大不同，在后者中，层状微观结构在高应变下会分解。超细晶粒结构和无孔隙使得Cu30Mo70复合材料的维氏硬度值为600，Cu50Mo50复合材料的维氏硬度值为475。制备具有高强度以及精细定向微观结构组合的Cu30Mo70纳米复合材料的能力对于热电应用应该具有吸引力。
