Variable amplitude loading of additively manufactured Ti6Al4V subjected to surface post processes

Critical Raw Materials Saving by Protective Coatings under Extreme Conditions: A Review of Last Trends in Alloys and Coatings for Aerospace Engine Applications

“…Post-processing applied on additive manufactured Ti-6Al-4V components show enormous potential in improvement of the alloy’s quality, e.g., by HIP process which leads to a homogenous microstructure and can reduce the porosity of titanium alloy parts produced by selective laser melting (SLM) [ 89 ]. In addition to internal defects and inhomogeneous microstructure, alloys fabricated by AM processes like laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) can present a rough surface, where surface features can act as stress concentration factors that are responsible for strong reduction of fatigue strength with respect to conventionally manufactured materials [ 90 ]. Then, this aspect often requires additional surface post-processing stages on additive manufactured components, like surface machining, electropolishing, chemical polishing, and shot peening.…”

“…Then, this aspect often requires additional surface post-processing stages on additive manufactured components, like surface machining, electropolishing, chemical polishing, and shot peening. Different surface post-processing methods on L-PBF and EB-PBF Ti-6Al-4V alloys have been analyzed in a recent work by Kahlin et al [ 90 ] in order to reduce surface roughness and control the residual stresses in the material, so to increase the fatigue life of the alloy. A specific paragraph dedicated to laser shot peening (LSP) on Ti-based alloys is reported later.…”

Machine Learning Based Predictions of Fatigue Crack Growth Rate of Additively Manufactured Ti6Al4V

“…Consequently, it is widely adopted in aerospace and biomedical applications which predominantly are geometrically complex shapes. This material is responsible for higher tool wear and worse machined surface integrity [1][2][3]. Many cutting tool materials are in fact chemically reactive to the titanium alloys, which makes it difficult to machine using traditional methods.…”

“…The independent variables include the post-processing technique, the built orientation during fabrication, and the stress intensity factor. These three parameters significantly influence the FCGR and are independent of each other [3,11,[30][31][32][33]. Given these three independent variables, the ML models are used to estimate the FCGR of Ti-64 alloy.…”

Micro-machining of additively manufactured metals: a review

“…They include geometrical defects, difficulty to control dimensional and form tolerances (Denti and Sola [23]); rough surfaces, thermal-induced distortion, shrinkage cavity, balling, stair-case effects, and dimensional inaccuracy (Kumar [24], Hamidi et al [25], Maleki et al [26], Tian et al [27]); metallurgical defects such as microcrack, thermal-induced microstructural change, grain size variation, preferred grain texture, porosity, and anisotropic mechanical properties (Teng et al [28], Maskery et al [29]); detrimental residual stress (Jawade et al [30]). Tiny defects can play a decisive role in the mechanical behavior of AM material, especially on the relationship between fatigue behavior and surface finishing (Azarniya et al [31], Kahlin et al [32]). Most of these limitations are primarily related to the process nature, which is very complex in terms of the thermo-mechanical phenomenon and limited available knowledge (Yadroitsev and Smurov [33], Zinovieva et al [34]).…”