Influence of Temperature and Stress Ratio on the Low-Cycle Fatigue Behavior of Trimarc-1 /Ti-6Al-2Sn-4Zr-2Mo
SourceThe results of an experimental investigation of load-controlled isothermal low cycle fatigue behavior of a titanium matrix composite (TMC) are discussed. The TMC was composed of Ti-6Al-2Sn-4Zr-2Mo matrix (wire) reinforced with silicon-carbide (Trimarc-1)™ fibers. The composite panels were constructed by alternating layers of matrix wire and fiber using a wire-winding technique. The panels were unidirectional with a [0]10 layup and fiber volume fraction ≈ 0.29. The longitudinal fatigue data showed good correlation with other TMC systems at both positive and negative stress ratios. The Walker equation was successful at correlating the longitudinal S-N data for stress ratios R = -1.3 and 0.1, and for predictions at R = 0.5 and 0.7. The maximum fiber stress versus cycles to failure for several unidirectional TMC systems at similar test conditions consolidate to a narrow band, indicating that the life is fiber dominated. The S-N behavior of the TMC, subjected to transverse fatigue loading, was successfully predicted using the matrix S-N data and a net-section model.