Investigation on the evolution mechanism of dislocation in nano-cutting of FeCoNiCrAlx high entropy alloy

Abstract

The element content has a very important influence on the overall properties of high-entropy alloys, which leads to different nano-cutting mechanisms. In order to explore the influence of Cr and Al contents on dislocation evolution mechanism in nano-cutting of FeCoNiCrAlx high-entropy alloy, nano-cutting of FeCoNiCrAlx high entropy alloy with different Cr and Al contents was simulated at 100 K by molecular dynamics simulation method, and It focuses on the comparison of Von mises, Shear strain, cutting force, cutting temperature, dislocation and phase transformation with different element contents. The results show that, at the same cutting speed, the chip thickness with Fe20Co20Ni20Cr24Al16 is less than that of Fe20Co20Ni20Cr30Al10, and the shear strain with Al content of 16% is higher than that with Al content of 10% at the same cutting depth. There is no uniform rule that the cutting force in [100], [010] and [001] directions is influenced by cutting speed and depth under different element contents，At different cutting speeds, the minimum cutting forces in the [100] direction of Fe20Co20Ni20Cr24Al16 and Fe20Co20Ni20Cr30Al10 are 92 Nn and 83 Nn, respectively, and the minimum cutting forces in the [001] direction of Fe20Co20Ni20Cr24Al16 and Fe20Co20Ni20Cr30Al10 are 82 Nn and 74 Nn, respectively. With the increase of cutting speed and cutting depth, the cutting temperature increases obviously, and the maximum increase amplitude of cutting temperature at different cutting depths is about 1.25 times that at different cutting speeds. The dislocation density of 1/6 < 112 > (Shockley) is the largest and the number of atoms in FCC structure is the largest under any cutting parameters. At different cutting speeds, the maximum dislocation density of 1/2 < 110 > (Perfect) of Fe20Co20Ni20Cr30Al10 is about 1.9 times that of Fe20Co20Ni20Cr24Al16, and the maximum dislocation density of 1/6 < 112 > of Fe20Co20Ni20Cr30Al10 is about 1.45 times that of Fe20Co20Ni20Cr24Al16.