Experimental Study on Uniaxial Time-Dependent Cyclic Deformation of POM/PTFE Blends

The uniaxial time-dependent cyclic deformation of POM/PTFE blends was studied experimentally under the stress-controlled and strain-controlled loading. The volume fraction of PTFE in the POM/PTFE blends was 20%. It was shown that the creep behavior of POM/PTFE blends is better than that of POM. In the cyclic strain-controlled experiments, the responded stress amplitude has a close relationship with the applied strain amplitude and strain rate. As a result of stress relaxation, the responded stress amplitude decreases as the hold time at peak strain increases. Ratcheting occurs in the blends subjected to asymmetric stress-controlled cyclic loading, and the ratcheting strain depends on the applied stress amplitude and stress rate. Hold time at peak stress and low stress rate lead to an increased ratcheting strain. The POM/PTFE blends will fail as the hold time at peak stress is longer than a critical value.