Super Long Life Fatigue Properties of Al-Si Eutectic Alloy by Rotating-Bending and Tension-Compression Fatigue Tests.

A comparison of fatigue strength sensitivity to defects for materials manufactured by AM or traditional processes

“…Thus, for instance, the √ area model from Murakami-Endo [24] can be applied to define the relationship between the ∆K th − √ area. Alternatively, the precise properties for a given AM material can be determined by performing targeted fatigue tests with artificial micronotches, which possess a larger √ area than the material defects, as was done in [18] for AM and in [17,60,85] for traditional processes.…”

Archives of Metallurgy and Materials

“…Castings made of aluminum alloys usually contain various structural discontinuities, which have an essential influence on the strength and fatigue life of these alloys. Investigations related to the influence of precipitates and structural defects on alloy durability have been presented in several papers, of which the papers of Y. Murakami [6,7] should be quoted. Structural discontinuities can constitute spaces unfilled with metal or non-metallic inclusions, which decrease the mechanical properties of castings [8].…”

“…1 provides Equation (6), while for Alloy No. 2 -Equation(7). The correlation coefficients are equal to R = 0.93 for Alloy No.…”

X-Ray CT Inspection for Porosities and Its Effect on Fatigue of Die Cast Aluminium Alloy

“…The variety of defects has prevented us from understanding the fatigue behavior to evaluate the fatigue reliability of die cast materials and structures. To elucidate the fatigue properties of cast aluminium alloys, many researchers have studied the effects of porosities (1)~ (15) , silicon phases (16), (17) , dendrite arm spacing (18)~ (20) , cast surface (10) , heat treatment (2), (21) , mean stress (1), (18) , variable stress amplitude (7), (22) , and corrosive environments (8), (10), (23) . And also, the crack propagation characteristics (21), (24) and giga-cycle fatigue behaviors (8), (9), (13), (14), (19) have been investigated.…”

“…Most of conventional approaches to fatigue have claimed that the fatigue crack is initiated at the maximum defect and grows up to final failure surface. For example, Murakami's square-root area parameter model (25) can predict the fatigue limit based on the maximum defect area and the Vickers hardness, and has been applied not only to steels but also to cast aluminium alloys (5), (10),(12)~(14), (16) . Most of the crack growth models (2),(4),(6),(7), (17), (19) to predict the fatigue life also start from the crack initiation at the maximum stress-raiser, that is, the maximum defect.…”