Numerical Research On Mechanical Properties Of Graphyne

Graphyne is a new type of carbon-based nanomaterial with good optical and electrical properties,which make it used in various field,such as electronic engineering,solar cell,batteries.The mechanical properties of graphyne(GY)and graphyne nanotube(GNT)are of great significance for their functionalization.In our work,the mechanical properties of GY and GNT under uniaxial tension were systematically studied using molecular dynamics method.The contents are as follows:(1)The effects of temperature,chiral angle and strain rate on the uniaxial tensile properties of?-,?-,?-and?-GY were systematically analyzed.When the chiral angle increases from 0°to 30°,the ultimate stress and strain also show a monotonically decreasing trend,with a maximum magnitude of 24%.In the case of small deformation,all types of GYs show isotropic characteristics;when the strain is large enough(>0.1),they show anisotropic mechanical properties for different chiral angles.It was found that the strength and toughness of these GYs decrease monotonically with a maximum magnitude of 48%when the temperature increases from 100K to1000K.It is also found that,with the increase of the strain rate,the ultimate stress and strain increases.Especially for the?-GY,they can be increased by 5.45%,7.56%,respectively.(2)The effects of high-temperature annealing on the uniaxial tensile properties of bilayer?-GY(BLGY)and have been systematically studied.Compared with single-layer graphyne(SLGY),the mechanical properties of BLGY are more sensitive to the change of the temperature:when T=100K,the ultimate stress of the BLGY is the same as that of the SLGY;but when T=1000K,the ultimate stress of the BLBY becomes?50%of that of the SLGY.After high temperature annealing treatment(T?500K),interlayer bonding occurs in BLGY,which results in the strength reduction and toughness enhancement of the BLGY.The ultimate strain can increase by 63.98%and the strength dec reases by 35.41%.(3)The effects of temperature and chirality on the mechanical properties of C₃₁and C₆₃ graphyne nanotubes(GNT)were systematically studied.The results show that both of them have good strength(?120GPa)and toughness(?0.6),due to the carbon triangle structures in them.Different from the brittle bahaviours of?-GNT,C₃₁-and C₆₃-GNT also show good toughness under low temperatures(<100K).It is also found,with the increase of the temperature,their ultimate stress and strain decreases.Their ultimate stress and strain also falls when the the chiral angle increase.