On the effect of pre-strain and pre-fatigue on the monotonic behaviour of ultra-high strength steels

Abstract

The mechanical behaviour of three ultra-high strength steels has been assessed; AerMet100, 300M and the recently developed corrosion resistant high strength steel, MLX-17. Material heat treatment profiles have been utilised to provide performance optimised for the aerospace industry and specimens have been tested to explore tensile and fatigue properties, in particular when combined with pre-strain to simulate the effects of overload. Testing of this kind has not been reported within the literature, particularly amongst ultra-high strength and corrosion-resistant steels. Baseline mechanical performance for all three materials in their heat-treated conditions has been established and properties such as yield strength and ultimate tensile strength have been assessed following a 75% and 95% pre-strain as well as fatigue in combination with a 75% and 95% pre-strain. Under all loading conditions, resultant tensile mechanical properties are not seen to witness a substantial degradation in performance, but an improvement in terms of yield strength and UTS, due to the role of work hardening. An alloy comparison has been carried out and responses are seen to vary slightly as a result of material microstructure. Correlation of pre-strain and pre-fatigue results with respect to baseline properties and microstructure has contributed to advancing the understanding of the mechanical behaviour of the aforementioned ultra-high strength steels.

Effect of pre-strain on high cycle fatigue property of TWIP steel

“…Among all fatigue test failure samples, only those whose fracture is within the effective interval can be called valid samples. Although the origin of the fracture is not the same, but can see three typical zones, there are the origin zone, propagation zone and instantaneous fracture zone [15].…”

Mechanical Properties and Simulation Method of Structural Steel After High Cycle Fatigue Damage (Icass’2020)

“…In terms of experimental research, Moćko [1] studied the effects of pre-fatigue on the DP 500 steel during tensile tests at low and high strain rates. Cockings [2] studied the effect of pre-strain and pre-fatigue on the monotonic behavior of AerMet100, 300M, and MLX-17 steels. Zhang [3] studied the residual strength of Q690 high-strength steel with pre-fatigue damage through a static tensile test.…”

Mechanical Properties and Simulation Method of Structural Steel After High Cycle Fatigue Damage

“…In terms of experimental research, Moćko [1] studied the effects of pre-fatigue on the DP 500 steel during tensile tests at low and high strain rates. Cockings [2] studied the effect of prestrain and pre-fatigue on the monotonic behavior of AerMet100, 300M, and MLX-17 steels. Zhang [3] studied the residual strength of Q690 high-strength steel with pre-fatigue damage through a static tensile test.…”