Effect of VGCNF on high-temperature deformation performance and softening mechanism of aluminum matrix

• Published in: Journal of alloys and compounds 2020-03, Vol.818, p.152923, Article 152923
• Main Authors: Guo, Ying, Liu, Xin-gang, Xu, Zhe-feng, Li, Wen-quan, Sasaki, Gen
• Format: Article
• Language: English
• Subjects: Aluminum; Aluminum matrix composites; Base metal; Carbon fibers; Composite materials; Deformation analysis; Deformation effects; Dynamic recrystallization; Electron backscatter diffraction; Grain refinement; High temperature; High-temperature deformation; Load transfer; Microstructure; Morphology; Nanofibers; Plasma sintering; Softening; Softening mechanism; Spark plasma sintering; VGCNF/Al composite
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.152923

Vapor-grown carbon nanofiber (VGCNF) reinforced aluminum (Al) matrix composites were prepared by spark plasma sintering. Isothermal compression experiments were conducted over a temperature range of 573 K–723 K at strain rates from 0.01 s−1 to 1 s−1. The effect of the addition of VGCNF on the thermal deformation properties of Al matrix was investigated by comparison with pure Al. The results indicate that the composite material has greater high-temperature strength than pure Al. VGCNF withstands stress through the load transfer mechanism in the Al matrix, however, it causes a significant change in the microstructure of the Al matrix. Lattice distortion of the base metal and grain refinement improve the strength of the material. During the thermal deformation process, the VGCNF/Al composite clearly exhibited softening. The difference in the morphology of the reinforced mass before and after the thermal deformation indicated that the sliding of tubular VGCNF was one of the factors leading to the softening. The microstructure after thermal deformation was analyzed by electron backscatter diffraction. It was found that VGCNF promoted the continuous dynamic recrystallization of the Al matrix, which led to softening of the material. •VGCNF/Al appears abnormal phenomenon of softening at high temperature deformation.•The relative slip between VGCNF reduces the deformation resistance of the composites.•The addition of VGCNF promoted the continuous dynamic recrystallization of aluminum matrix.•The degree of dynamic recrystallization of VGCNF/Al and pure aluminum increases with the decrease of Z parameter value.