Experimental characterization of roughness-induced crack closure in Al-Li 2090 alloy

A macrostructural model for simulating the combined effects of roughness and plasticity induced fatigue crack closure

“…At the threshold, Forsyth's [24] stage I crystallographic growth occurs creating a serrated fracture surface. However, many alloys such as Al 2024, Al 7050, and the Al-Li alloys also exhibit tortuous crack growth paths under stage II growth in the Paris regime [6,[25][26][27][28][29]. Aluminum alloys which exhibit a tortuous crack growth path in the Paris regime are attractive to the aerospace industry because the RICC slows crack growth giving panels built from these alloys more useful design life.…”

“…Since the pioneering work of Walker and Beevers [1] the RICC mechanism has been widely recognized as an important mechanism of crack closure [3][4][5][6]. RICC has been related to a number of material and loading conditions that affect the size and pattern of the tortuous crack growth path including: the material grain size [7][8][9][10][11][12], the applied stress intensity factor range [7,11,13], alloying particles and phases [10,11,[13][14][15][16], alloy aging [14,17], and crystallographic texture [10].…”