Fatigue properties of SLM-produced Ti6Al4V with various post-processing processes

Effect of HIP post-processing at 850 °C/200 MPa in the fatigue behavior of Ti-6Al-4V alloy fabricated by Selective Laser Melting

“…9, where stress values are normalised using the effective stress previously defined in equation ( 1). It can be observed that the low-temperature high-pressure HIP processes, 850 • C and 200 MPa here and 800 • C and 200 MPa in Moran et al [22], result in a better fatigue response in comparison with the conventional HIP cycle of 100 MPa and 900 • C or 920 • C applied by Kasperovich et al [6] and Mertova et al [39], respectively. Therefore, the beneficial effect of temperature reduction is patent in the shift of fatigue behaviour as a function of temperature; the fitted curves in this HCF range are ordered, from top to bottom, in the following order: 800 • C [22], 850 • C, 900 • C [6] and 920 • C [39].…”

“…Yan et al [37] studied the effect of heat treatment on the phase transformation and mechanical properties of Ti-6Al-4V fabricated by SLM, and analysed the tensile properties for different heat treatments at 800, 900, 920, 950 and 1080 • C, as well as HIPed at 900 • C / 120 MPa / 2 h. They also present fatigue results for as-built conditions, HT at 900 • C and HIP at 900 • C, respectively. Mertova et al [39] and Roudnicka et al [10] also explored the influence of surface machining and postprocessing by HIP on the fatigue properties of SLM produced components.…”

“…Cutolo et al [13] studied the fatigue behaviour using miniaturized samples with a circular cross section of 2.5 mm in diameter. The authors [35] As-built + HT 670 [38] As-built + HT 640 [39] As-built / annealed 820 [10] As-built / annealed 820 [22] Standard HIP 920 investigated two different heat treatments for Ti-6Al-4V produced by SLM, namely, stress-relief (SR) and HIP. For SR, the samples were heated at 850 • C for 2 h followed by air cooling, while for HIP the samples were heated at a temperature of 920 • C at a pressure of 1000 bar for 2 h. All the samples were tested in as-built surface conditions.…”

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

“…Many cutting tool materials are in fact chemically reactive to the titanium alloys, which makes it difficult to machine using traditional methods. To address these problems, apart from traditional manufacturing methods, Laser Powder Bed Fusion (L-PBF) has become a popular metal additive manufacturing method for producing geometrically complex shapes [4][5][6]. L-PBF is an additive manufacturing process in which successive layers of powder are selectively melted by the interaction of a highenergy-density laser beam.…”

Additive manufacturing and mechanical properties of titanium lattices for biomedical applications

“…This is why it is crucial to take into consideration the high cycle fatigue life behaviour of these materials, and in particular tension-tension fatigue, when developing a new generation of metallic biomaterials. As we know, as-built SLM-produced material tends to have a lower fatigue limit compared to machined components [247,248], which is one of the major drawbacks of additive manufacturing. This poor fatigue strength is believed to be notably due to the surface state of the as-built samples that present a high surface roughness [135,249] as well as residual micro porosity that can be found within the bulk material [250].…”