journal article·2022-09Open access

Fatigue strength of LPBF Ti6Al4V machined under flood and cryogenic lubri-cooling conditions

Rachele Bertolini, Alberto Campagnolo, Marco Sorgato, Andrea Ghiotti, Stefania Bruschi, Giovanni Meneghetti

Abstract

In the present work, Ti6Al4V specimens were manufactured by Laser Powder Bed Fusion (LPBF), heat treated and machined using two lubri-cooling conditions, i.e. flood or cryogenic, the latter being useful to improve the machined surface integrity. These specimens were characterised in terms of micro-hardness, microstructure, residual stresses and surface topography. Afterwards, they were fatigue tested under rotating bending loading and the fracture surfaces were analysed by SEM to identify the killer defects. Finally, the experimental fatigue results were compared with the theoretical estimations according to both the Murakami and El Haddad-Smith-Topper models.
Source: openaire · Quality: candidate unverified · Source record ↗

Research context

OpenAlex topics: Additive Manufacturing Materials and Processes · Surface Treatment and Residual Stress · Advanced machining processes and optimization

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

References (71)

Show source-provided references
1. Fatigue behaviour of additive manufactured materials: An overview of some recent experimental studies on Ti-6Al-4V considering various processing and loading direction effects10.1111/ffe.13000 ↗
2. Rapid manufacturing of dental prostheses by means of selective laser sintering/melting
3. Efficient cooling with tool inserts manufactured by electron beam melting10.1108/13552540710750870 ↗
4. Metal Fabrication by Additive Manufacturing Using Laser and Electron Beam Melting Technologies10.1016/S1005-0302(12)60016-4 ↗
5. Design guidelines for laser additive manufacturing of lightweight structures in TiAl6V410.2351/1.4885235 ↗
6. An Overview of Densification, Microstructure and Mechanical Property of Additively Manufactured Ti-6Al-4V — Comparison among Selective Laser Melting, Electron Beam Melting, Laser Metal Deposition and Selective Laser Sintering, and with Conventional Powder10.5772/59275 ↗
7. Metallurgy of additive manufacturing: Examples from electron beam melting
8. An Overview of Additive Manufacturing of Titanium Components by Directed Energy Deposition: Microstructure and Mechanical Properties10.3390/app7090883 ↗
9. On the mechanical behaviour of titanium alloy TiAl6V4 manufactured by selective laser melting: Fatigue resistance and crack growth performance10.1016/j.ijfatigue.2012.11.011 ↗
10. Residual stresses in selective laser sintering and selective laser melting10.1108/13552540610707013 ↗
11. Mechanical behavior of additive manufactured, powder-bed laser-fused materials10.1016/j.msea.2015.10.068 ↗
12. Critical assessment of the fatigue performance of additively manufactured Ti–6Al–4V and perspective for future research10.1016/j.ijfatigue.2015.12.003 ↗
13. Anisotropic high cycle fatigue behavior of Ti–6Al–4V obtained by powder bed laser fusion10.1016/j.ijfatigue.2016.04.032 ↗
14. Additive manufacturing of fatigue resistant materials: Challenges and opportunities10.1016/j.ijfatigue.2017.01.001 ↗
15. Low-Cycle Fatigue Behaviour of AISI 18Ni300 Maraging Steel Produced by Selective Laser Melting10.3390/met8010032 ↗
16. Fatigue of additively manufactured 316L stainless steel: The influence of porosity and surface roughness10.1111/ffe.13077 ↗
17. A review on the fatigue behavior of Ti-6Al-4V fabricated by electron beam melting additive manufacturing10.1016/j.ijfatigue.2018.09.022 ↗
18. The influence of additive manufacturing processing parameters on surface roughness and fatigue life10.1016/j.ijfatigue.2019.03.025 ↗
19. Densification behavior, microstructure evolution, and wear performance of selective laser melting processed commercially pure titanium10.1016/j.actamat.2012.04.006 ↗
20. Additive manufacturing of strong and ductile Ti–6Al–4V by selective laser melting via in situ martensite decomposition10.1016/j.actamat.2014.11.028 ↗
21. An overview of Direct Laser Deposition for additive manufacturing; Part II: Mechanical behavior, process parameter optimization and control
22. Microstructures of laser-deposited Ti–6Al–4V10.1016/j.matdes.2003.09.009 ↗
23. Influence of build orientation on static and axial fatigue properties of maraging steel specimens produced by additive manufacturing10.1016/j.prostr.2017.11.072 ↗
24. Effects of build orientation on fatigue behavior of Ti-6Al-4V as-built specimens produced by direct metal laser sintering10.1016/j.prostr.2020.02.032 ↗
25. Fatigue characterization of Titanium Ti-6Al-4V samples produced by Additive Manufacturing10.1016/j.prostr.2016.06.395 ↗
26. Influence of the finish cutting operations on the fatigue performance of Ti-6Al-4V parts produced by Selective Laser Melting10.1016/j.procir.2018.05.054 ↗
27. Analysis of defect generation in Ti–6Al–4V parts made using powder bed fusion additive manufacturing processes
28. Anisotropic tensile behavior of Ti–6Al–4V components fabricated with directed energy deposition additive manufacturing10.1016/j.actamat.2014.12.054 ↗
29. Fabrication of large Ti–6Al–4V structures by direct laser deposition10.1016/j.jallcom.2014.12.234 ↗
30. A comparison of fatigue strength sensitivity to defects for materials manufactured by AM or traditional processes10.1016/j.ijfatigue.2016.06.020 ↗
31. Low- and high-cycle fatigue resistance of Ti-6Al-4V ELI additively manufactured via selective laser melting: Mean stress and defect sensitivity10.1016/j.ijfatigue.2017.10.021 ↗
32. Metal fatigue : effects of small defects and nonmetallic inclusions
33. A new approach to correlate the defect population with the fatigue life of selective laser melted Ti-6Al-4V alloy10.1016/j.ijfatigue.2020.105584 ↗
34. Fatigue propagation threshold of short cracks under constant amplitude loading10.1016/S0142-1123(03)00065-3 ↗
35. Effects of defects on tensile and fatigue behaviors of selective laser melted titanium alloy in very high cycle regime10.1016/j.ijfatigue.2020.105795 ↗
36. An engineering estimation of fatigue thresholds from a microstructural size and Vickers hardness: application to wrought and additively manufactured metals10.1016/j.ijfatigue.2020.105796 ↗
37. Engineering estimation of the fatigue limit of wrought and defective additively manufactured metals for different load ratios10.1016/j.ijfatigue.2021.106530 ↗
38. An analysis of defects influence on axial fatigue strength of maraging steel specimens produced by additive manufacturing10.1016/j.ijfatigue.2018.08.034 ↗
39. Improving surface integrity and corrosion resistance of additive manufactured Ti6Al4V alloy by cryogenic machining10.1007/s00170-019-04180-5 ↗
40. Machining-induced surface integrity in titanium alloy Ti-6Al-4V: An investigation of cutting edge radius and cooling/lubricating strategies10.1016/j.jmapro.2021.12.016 ↗
41. Surface integrity in metal machining - Part II: Functional performance10.1016/j.ijmachtools.2021.103718 ↗
42. Analysis of tool wear in cryogenic machining of additive manufactured Ti6Al4V alloy10.1016/j.wear.2015.01.030 ↗
43. Influence of the machining parameters and cooling strategies on the wear behavior of wrought and additive manufactured Ti6Al4V for biomedical applications10.1016/j.triboint.2016.05.036 ↗
44. Fatigue life of machined Ti6Al4V alloy under different cooling conditions10.1016/j.cirp.2018.03.017 ↗
45. On the critical inclusion size of high strength steels under ultra-high cycle fatigue10.1016/j.msea.2006.04.068 ↗
46. Effect of small defects on the fatigue strength of martensitic stainless steels10.1016/j.ijfatigue.2019.06.021 ↗
47. A simple model to predict the very high cycle fatigue resistance of steels10.1016/j.ijfatigue.2010.12.010 ↗
48. Influence of defects, surface roughness and HIP on the fatigue strength of Ti-6Al-4V manufactured by additive manufacturing10.1016/j.ijfatigue.2018.07.020 ↗
49. Defect analysis and fatigue design basis for Ni-based superalloy 718 manufactured by selective laser melting10.1016/j.ijfatigue.2018.08.002 ↗
50. Resistance of direct metal laser sintered Ti6Al4V alloy against growth of fatigue cracks10.1016/j.engfracmech.2017.03.033 ↗
51. Fatigue crack growth behavior and microstructural mechanisms in Ti-6Al-4V manufactured by laser engineered net shaping10.1016/j.ijfatigue.2016.08.009 ↗
52. Crack propagation and fracture toughness of Ti6Al4V alloy produced by selective laser melting
53. Fatigue crack growth in additive manufactured products
54. Fracture mechanics and notch sensitivity10.1046/j.1460-2695.2003.00633.x ↗
55. A unified treatment of the mode I fatigue limit of components containing notches or defects10.1007/s10704-005-2183-0 ↗
56. Yoder G, Cooley L, Crooker T. A Critical Analysis of Grain-Size and Yield-Strength Dependence of Near-Threshold Fatigue Crack Growth in Steels. Fract. Mech. Fourteenth Symp. I Theory Anal., 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International; n.d., p. I-348-I-348–18. 10.1520/STP37081S.
57. Fatigue Crack Propagation of Short Cracks10.1115/1.3443647 ↗
58. Prediction of non propagating cracks10.1016/0013-7944(79)90081-X ↗
59. Influence of additive manufacturing-induced anisotropy on tool wear in end milling of Ti6Al4V10.1016/j.triboint.2020.106200 ↗
60. Fatigue performance of additive manufactured TiAl6V4 using electron and laser beam melting10.1016/j.ijfatigue.2016.05.001 ↗
61. Beyond the orthogonal: on the influence of build orientation on fatigue crack growth in SLM Ti-6Al-4V10.1016/j.ijfatigue.2018.06.038 ↗
62. ASTM E92-17, Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials. ASTM International, West Conshohocken, PA; 2017. 10.1520/E0092-17.
63. A critical evaluation of the microstructural gradient along the build direction in electron beam melted Ti-6Al-4V alloy10.1016/j.msea.2018.12.016 ↗
64. ISO 25178-2:2012 Geometrical product specifications (GPS) — Surface texture: Areal — Part 2: Terms, definitions and surface texture parameters. ISO/TC 213; 2012.
65. ISO 12107:2003, Metallic materials - Fatigue testing - Statistical planning and analysis of data. 2003.
66. ASTM E739-10 - Standard practice for statistical analysis of linear or linearized stress-life (S-N) and strain-life (ε-N) fatigue data. ASTM International; 2015.
67. Essential structure of S-N curve: Prediction of fatigue life and fatigue limit of defective materials and nature of scatter10.1016/j.ijfatigue.2020.106138 ↗
68. Improving surface integrity of additively manufactured GP1 stainless steel by roller burnishing10.1016/j.cirp.2020.04.015 ↗
69. A literature survey on the stability and significance of residual stresses during fatigue10.1111/j.1460-2695.2007.01102.x ↗
70. Interaction effect of adjacent small defects on the fatigue limit of a medium carbon steel10.1111/ffe.12482 ↗
71. The influence of interacting small defects on the fatigue limits of a pure iron and a bearing steel10.1016/j.ijfatigue.2020.105560 ↗