Investigation on the tensile properties of nanocrystalline NiFeCrCoMn high-entropy alloy containing prefabricated crack

The tensile behavior of prefabricated cracked nanocrystalline NiFeCrCoMn high-entropy alloys (HEAs) under different strain rates and temperature service conditions was investigated using molecular dynamics methods. The results showed that the higher the strain rate, the greater the peak stress and average flow stress. A high strain rate induced a high dislocation density, resulting in an increase in the peak stress. At high strain rates, the reduction in delamination defects during plastic deformation leads to the inability to consume stress concentration in a timely manner, resulting in an increase in the average flow stress. At high temperatures, the dislocation density was suppressed, the number of amorphous atoms increased, the HEA underwent high-temperature softening, and the peak stress and average flow stress decreased with increasing temperature. In addition, pre-formed cracks tend to propagate toward areas with lower stress and extend along the grain boundaries of the grains.