摘要
Fatigue crack initiation at different stress levels was studied. Two modes of fatigue crack initiation are found. One is that fatigue crack initiates in the alloy matrix away from the Nd rich particles, which is often related to the cracking of equiaxed α particles. The other is that fatigue crack initiation is associated with the Nd rich particles. When the maximum nominal stress is less than 450 MPa, all of fatigue cracks initiate in the matrix of the alloy. With the increasing of the applied stress, the probability of the second mode increases gradually.
Fatigue crack initiation at different stress levels was studied. Two modes of fatigue crack initiation are found. One is that fatigue crack initiates in the alloy matrix away from the Nd rich particles, which is often related to the cracking of equiaxed α particles. The other is that fatigue crack initiation is associated with the Nd rich particles. When the maximum nominal stress is less than 450 MPa, all of fatigue cracks initiate in the matrix of the alloy. With the increasing of the applied stress, the probability of the second mode increases gradually.
