Crack-resistance curve of a Zr-Ti-Cu-Al bulk metallic glass with extraordinary fracture toughness

The aim of this report is to examine the nature of accumulation of ratcheting strain (ɛr) vis-a-vis in situ substructural and microstructural variations in 304LN stainless steel under varied asymmetric cyclic loading (ACL) conditions. For this purpose, a series of ACL experiments have been carried out on cylindrical tensile specimens under different combinations of mean stress (σm) and stress amplitude (σa). In one set of experiments, σm has been varied between 50 and 150 MPa keeping σa constant, while in a second set σm has been kept constant and σa is varied between 300 and 400 MPa. From the results it can be inferred that ɛr increases from cycle to cycle for ACL tests and the phenomenon is considered to be governed by the associated mechanics and mechanisms of deformation. Fatigue life of a specimen can either increase or decrease depending upon the test condition, which induces different variations in dislocation density, sub-grain size or micro-damage formation.

Influence of asymmetric cyclic loading on substructure formation and ratcheting fatigue behaviour of AISI 304LN stainless steel

Corrosion fatigue life prediction of a steel shaft material in seawater

The effect of tensile prestraining on the ductile fracture behaviour of two varieties of Cu-strengthened HSLA steels has been studied. It was observed that for both the HSLA steels the fracture toughness, JC, remained invarient up to 2% prestrain, beyond which it decreased deleteriously. The nature of variation of fracture toughness with prestrain has been explained in terms of variation of the tensile flow properties of the steels with prestrain. A model correlating fracture toughness and the tensile flow properties has been proposed and it is demonstrated that the predictions of the model matched closely with the experimental observations.

Effect of prestrain on fracture toughness of HSLA steels

On the path-dependence of the fracture locus in ductile materials: Experiments

Corrosion fatigue crack growth behaviour of naval steels

Failure analysis of coal pulverizer mill shaft

http://eprints.nmlindia.org/274/1/P._K._Singh.pdf

Effect of cyclic loading on elastic–plastic fracture resistance of PHT system piping material of PHWR

The effects of prestrain on the ductile fracture behavior of two varieties of Cu-strengthened high-strength low-alloy (HSLA) steels have been investigated through stretch-zone geometry measurements. It is noted that the ductile fracture-initiation toughness of both the steels remained unaltered up to prestrains of ∼2 pct, beyond which the toughness decreased sharply. A methodology for estimating the stretch-zone dimensions is proposed. Fracture-toughness estimations through stretch-zone width (SZW) and stretch-zone depth (SZD) measurements revealed that the nature of the variation of ductile fracture toughness with prestrain can be better predicted through SZD rather than the SZW measurements. However, for the specimen geometries and prestrain levels that were investigated, none of these methods were found suitable for quantifying the initiation fracture toughness.

V R Ranganath

Papers

Effect of prestrain on fracture toughness of HSLA steels

Corrosion fatigue crack growth behaviour of naval steels

Failure analysis of coal pulverizer mill shaft

Effect of cyclic loading on elastic–plastic fracture resistance of PHT system piping material of PHWR

Effect of prestrain on stretch-zone formation during ductile fracture of cu-strengthened high-strength low-alloy steels