Abstract
? 2022 Elsevier B.V.In this paper, advanced hot isostatic pressing (HIP) subjected to high and intermediate cooling rate (HCR & ICR) were exploited to close keyholes and tune the microstructure of SLMed Ti-34 Nb-13Ta-5Zr-0.2 O alloys (TNT5Zr-0.2 O, wt%). XRD analysis along with SEM and TEM micrographs reveal single beta phase in grain matrix of as-fabricated TNT5Zr-0.2 O (TNT5Zr-0.2 O-AF), TNT5Zr-0.2 O-HCR, TNT5Zr-0.2 O-ICR alloys. Additionally, high-angle annular dark-field (HAADF) micrographs show discrete large Ti-rich α grain boundary precipitates in TNT5Zr-0.2 O-ICR alloy. Tensile properties show that TNT5Zr-0.2 O-AF alloy possessed high UTS of 975 ± 12 MPa, and elongation of 4.9% ± 0.3%; the TNT5Zr-0.2 O-ICR alloy obtained slightly higher UTS (1036 ± 26 MPa) and lower elongation (3.0% ± 0.3%). S-N curves demonstrate fatigue limit of TNT5Zr-0.2 O-ICR alloy (150 MPa) is slightly higher than the counterpart of TNT5Zr-0.2 O-AF alloy (130 MPa), and slip-band cracking phenomenon was observed in both alloys. Advanced HIP subjected to intermediate cooling rate functions well to close SLM-processed keyholes but the resistance to fatigue is not markedly enhanced; the addition of proper amount oxygen interstitial solutes in TNTZ-O alloy is regarded as an inexpensive, effective strengthening technique for load-bearing biomedical applications.
NSTL
Elsevier