Functionally graded（FG） carbon nanotubes（CNT） and nano-silicon carbide（nSiC） reinforced aluminium（Al）matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state s...Functionally graded（FG） carbon nanotubes（CNT） and nano-silicon carbide（nSiC） reinforced aluminium（Al）matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state spark plasma sintering processes.The CNTs were well-dispersed in the Al particles using the nSiC as a solid mixing agent.Two different types of multi-walled CNTs were used to add different amounts of CNTs in the same volume.The ball milled Al—CNT—nSiC and Al—CNT powder mixtures were fully densified and demonstrated good adhesion with no serious microcracks and pores within an FG multilayer composite.Each layer contained different amounts of the CNTs,and the nSiC additions showed different microstructures and hardness.It is possible to control the characteristics of the FG multilayer composite through the efficient design of an Al—CNT—nSiC gradient layer.This concept offers a feasible approach for fabricating the dualnanoparticulate-reinforced Al matrix nanocomposites and can be applied to other scenarios such as polymer and ceramic systems.展开更多
Powder mixture of ball-milled aluminium and functionalized multi-walled carbon nanotubes was compacted via spark plasma sintering （SPS） to study effects of sintering temperature and heating rate. An increase in sint...Powder mixture of ball-milled aluminium and functionalized multi-walled carbon nanotubes was compacted via spark plasma sintering （SPS） to study effects of sintering temperature and heating rate. An increase in sintering temperature led to an increase in crystallite size and density, whereas an increase in heating rate exerted the opposite effect. The crystallite size and relative density increased by 85.0% and 14.3%, respectively, upon increasing the sintering temperature from 400 to 600℃, whereas increasing the heating rate from 25 to 100 ℃/min led to respective reduction by 30.0% of crystallite size and 1.8% of relative density. The total punch displacement during SPS for the nanocomposite sintered at 600 ℃ （1.96 mm） was much higher than that of the sample sintered at 400 ℃ （1.02 mm） confirming positive impact of high sintering temperature on densification behaviour. The maximum improvement in mechanical properties was exhibited by the nanocomposite sintered at 600 ℃ at a heating rate of 50℃/min displaying microhardness of 81 4- 3.6 VHN and elastic modulus of 89 4- 5.3 GPa. The nanocomposites consolidated at 400 ℃ and 100 ℃/min, in spite of having relatively smaller crystallite size, exhibited poor mechanical properties indicating the detrimental effect of porosity on the mechanical properties.展开更多
文摘Functionally graded（FG） carbon nanotubes（CNT） and nano-silicon carbide（nSiC） reinforced aluminium（Al）matrix composites have been successfully fabricated using high-energy ball milling followed by solid-state spark plasma sintering processes.The CNTs were well-dispersed in the Al particles using the nSiC as a solid mixing agent.Two different types of multi-walled CNTs were used to add different amounts of CNTs in the same volume.The ball milled Al—CNT—nSiC and Al—CNT powder mixtures were fully densified and demonstrated good adhesion with no serious microcracks and pores within an FG multilayer composite.Each layer contained different amounts of the CNTs,and the nSiC additions showed different microstructures and hardness.It is possible to control the characteristics of the FG multilayer composite through the efficient design of an Al—CNT—nSiC gradient layer.This concept offers a feasible approach for fabricating the dualnanoparticulate-reinforced Al matrix nanocomposites and can be applied to other scenarios such as polymer and ceramic systems.
基金supported financially by the‘‘SERC Funding’’ from Department of Science and Technology,Government of India(No.SERC/ET-0388/2012)
文摘Powder mixture of ball-milled aluminium and functionalized multi-walled carbon nanotubes was compacted via spark plasma sintering （SPS） to study effects of sintering temperature and heating rate. An increase in sintering temperature led to an increase in crystallite size and density, whereas an increase in heating rate exerted the opposite effect. The crystallite size and relative density increased by 85.0% and 14.3%, respectively, upon increasing the sintering temperature from 400 to 600℃, whereas increasing the heating rate from 25 to 100 ℃/min led to respective reduction by 30.0% of crystallite size and 1.8% of relative density. The total punch displacement during SPS for the nanocomposite sintered at 600 ℃ （1.96 mm） was much higher than that of the sample sintered at 400 ℃ （1.02 mm） confirming positive impact of high sintering temperature on densification behaviour. The maximum improvement in mechanical properties was exhibited by the nanocomposite sintered at 600 ℃ at a heating rate of 50℃/min displaying microhardness of 81 4- 3.6 VHN and elastic modulus of 89 4- 5.3 GPa. The nanocomposites consolidated at 400 ℃ and 100 ℃/min, in spite of having relatively smaller crystallite size, exhibited poor mechanical properties indicating the detrimental effect of porosity on the mechanical properties.
