Crack growth in conventionally manufactured pure nickel, titanium and aluminum and the cold spray additively manufactured equivalents

Jones, Rhys; Kovářík, Ondřej; Ang, Andrew Siao Ming; Lang, Jeff

doi:10.1016/j.addlet.2022.100043

Cited by 7 publications

(8 citation statements)

References 16 publications

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“…As such, for both conventionally and AM Ti-6Al-4V the values of D (=2.79 × 10 −10 ) and p (=2.12) are true materials constants, and remain the same for each of these seventy seven tests. The mean value of A given in [49] for as-built AM Ti-6Al-4V surfaces is 62 MPa √ m. Extensions of this observation, namely that when allowance is made for the effect of the different build processes and post built processing on the terms ∆K thr and A then the da/dN versus ∆κ curves collapse to a single curve, to a wide range of conventionally manufactured, AM and cold spray additively manufactured (CSAM) materials are given in [53,54].…”

Section: Introductionmentioning

confidence: 90%

A Numerical Study into the Effect of Machining on the Interaction between Surface Roughness and Surface Breaking Defects on the Durability of WAAM Ti-6Al-4V Parts

Peng

Jones

Ang

et al. 2022

Metals

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The airworthiness certification of military aircraft requires a durability analysis be performed using linear elastic fracture mechanics (LEFM). Furthermore, such analyses need to use a valid small crack growth equation. This paper focuses on the effect of rough surfaces and the effect of machining the surface on the durability of AM parts using LEFM and a valid small crack growth equation for the material. To this end, this paper analyses the effect of surface roughness on wire and arc additively manufactured (WAAM) Ti-6Al-4V titanium parts and the effect of machining on the durability of a part. The analysis reveals that the life of the component is a relatively strong function of the degree of surface roughness, and that the durability of a specimen is a strong function of the local radius of the curvature of the trough. It also appears that surfaces with tall narrow roughness will not overly benefit from partial machining of the surface.

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Section: Introductionmentioning

confidence: 90%

A Numerical Study into the Effect of Machining on the Interaction between Surface Roughness and Surface Breaking Defects on the Durability of WAAM Ti-6Al-4V Parts

Peng

Jones

Ang

et al. 2022

Metals

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“…As illustrated in previous studies, [41][42][43][44][45][46] it appears that the variability in crack growth in addictively manufactured components can often be modeled using the Hartman-Schijve crack growth equation. 38,44 In this work, Equation 3 was used to compute the variability in the crack growth histories associated with various tests.…”

Section: Crack Growth Prediction In Waam-built Componentsmentioning

confidence: 91%

Assessment of mechanical and fatigue crack growth properties of wire + arc additively manufactured mild steel components

Shamir

Igwemezie

Lotfian

et al. 2022

Fatigue Fract Eng Mat Struct

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A study has been conducted to evaluate the mechanical and fatigue crack propagation properties of wire + arc additively manufactured ER70S‐6 components. A parallel‐built deposition strategy was employed to fabricate the additively manufactured wall. The hardness values were slightly higher at the bottom and top of the wall due to the presence of Widmanstätten ferrite and carbides. The characterization of mechanical properties in both orientations; parallel and perpendicular to the deposition direction showed a marginal difference in yield strength and ultimate tensile strength. The crack growth rates were correlated with linear elastic fracture mechanics parameter ΔK and compared with an oscillation‐built deposition strategy from the literature. The crack growth rates of both deposition strategies were found to be very similar to each other. Furthermore, it has been demonstrated that the variability in the crack growth histories can be reasonably well captured by using the NASGRO crack growth equation.

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“…In our paper, the Hartmann–Schijve (H-S) variant [ 24 ] of Forman equation was selected for its simplicity and capability to fit all three stages of the fatigue crack growth, i.e., the near-threshold, Paris, and cyclic fracture toughness regimes. The H-S formula already demonstrated its capability to fit the FCGR data from small specimen tests in [ 25 , 26 , 27 , 28 ]. The method to fit the H-S model to FCGR data must reflect the asymptotic behavior of the model.…”

Section: Methodsmentioning

confidence: 99%

Fatigue Crack Growth Rate Description of RF-Plasma-Sprayed Refractory Metals and Alloys

Kovářík

Klečka

2023

Materials

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A fitting method capable of describing the fatigue crack growth rate (FCGR) data in all stages of crack propagation by a simple Forman-style analytical formula was developed. To demonstrate its robustness, this method was used to quantify the fracture behavior of RF-plasma-sprayed W, Mo, W-Mo composite, and four selected Ni-based tungsten heavy alloys (WHA). The fitted FCGR parameters categorized the studied materials into two distinct sets. W, Mo, and W-Mo composite deposits made from inherently brittle refractory metals that contained a range of defects inherent to plasma spray process represented the first class. This class was characterized by low fracture toughness and a relatively wide range of fatigue crack growth thresholds. The second class of materials was represented by WHA. Here, the deposit defects were suppressed by liquid state diffusion that formed a typical WHA structure consisting of a Ni-rich matrix and large spherical W reinforcement particles. The WHA generally showed higher fatigue crack growth thresholds, but differed in fracture toughness values based on the W particle concentrations. The obtained fracture mechanical data represent a reference dataset of plasma-sprayed refractory materials, and their classification into groups clearly demonstrates the capabilities of the developed method to capture a wide range of different types of FCGR behavior.

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Crack growth in conventionally manufactured pure nickel, titanium and aluminum and the cold spray additively manufactured equivalents

Cited by 7 publications

References 16 publications

A Numerical Study into the Effect of Machining on the Interaction between Surface Roughness and Surface Breaking Defects on the Durability of WAAM Ti-6Al-4V Parts

A Numerical Study into the Effect of Machining on the Interaction between Surface Roughness and Surface Breaking Defects on the Durability of WAAM Ti-6Al-4V Parts

Assessment of mechanical and fatigue crack growth properties of wire + arc additively manufactured mild steel components

Fatigue Crack Growth Rate Description of RF-Plasma-Sprayed Refractory Metals and Alloys

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