Accession Number : AD0703577

Title :   FATIGUE FRACTURE IN A HIGH-STRENGTH LOW-ALLOY STEEL,

Corporate Author : DEFENCE STANDARDS LABS MARIBYRNONG (AUSTRALIA)

Personal Author(s) : Thompson,K. R. L. ; Araki,T. ; Uchiyama,I.

Report Date : 16 JUL 1968

Pagination or Media Count : 6

Abstract : The effect of strength and stress level upon the mode and rate of fatigue crack growth in A1S14340 steel was studied by electron microfractography. It is shown that the mode of crack growth at high-strength levels is by a combination of transgranular striation formation and intergranular prior austenite grain boundary cracking, whereas in the lower-strength material only transgranular fracture occurs. The effect of stress level is found to alter slightly the proportion of the two fracture modes. At high-strength levels, measurement of striation spacing at various crack lengths indicates that the rate of crack growth is a function of the applied stress and crack length. Using this relationship it is shown that as the applied stress decreases, crack initiation becomes increasingly important in determining fatigue life. (Author)

Descriptors :   (*STEEL, FRACTURE(MECHANICS)), FATIGUE(MECHANICS), CRACK PROPAGATION, STRESSES, AUSTRALIA

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE