|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||X-13: Microstructures and Tensile Properties of Ultrafine Structured Cu-5vol.%Al2O3 Nanocomposites Fabricated by Powder Compact Extrusion at Different Temperatures
||Dengshan Zhou, Deliang Zhang, Paul Munroe, Charlie Kong, Gang Sha, Zakaria Quadir, Wei Zeng
|On-Site Speaker (Planned)
The microstructures,tensile properties and fracture behavior of the extruded ultrafine grainedCu-5vol.%Al2O3samples were studied by detailed microstructural characterization,tensile testing and examination of the fracture surfaces and longitudinal sections of the fractured specimens. It wasfound that strain induced rapid growth of Cunanograins into ultrafine Cugrains occurred during extrusion even ata relatively lowtemperature of300oC.With increasing the extrusion temperature from300to900oC,the average Cu grain size increased from137to339nm,and the volume fraction and averagesize of thoseAl2O3nanoparticles larger than20nm increased from0.7and43to4vol.%and99nm,respectively.In the meantime,the dislocation density ofthe extruded samples decreased from1.1×1014to0.3×1014m-2.The Al2O3nanoparticles were predominantly located at the grain boundaries and junctions of theCu matrix.The changesofthemicrostructuresandconsolidation level ofthe extruded samples with increasing extrusion temperature led to significant changes of their tensile properties and fracture behavior,especially the elongation to fracture and tolerance to the surface flaws.The contributions of various strengthening mechanisms to the yield strength of the samples extruded at500and900oC,respectively,were analyzed,showing that grain boundary strengthening,dislocation hardening andAl2O3particle strengthening made major contributions.