Comparison of the Cracking Behavior of Powder Metallurgy and Ingot Metallurgy Ti-5Al-5Mo-5V-3Cr Alloys during Hot Deformation

Abstract

The hot workability of metallic materials is significantly dependent on its ability to form plastic without cracking and fracturing. In this work, the cracking behavior of powder metallurgy (PM) Ti-5Al-5Mo-5V-3Cr (Ti-5553) alloy, consolidated from powder mixture, at a deformation temperature range of 600 °C–850 °C and strain rate of 0.1 s−1–10 s−1, was investigated through isothermal compression tests. The cracking behavior of the as-cast ingot metallurgy (IM) Ti-5553 alloy, at a deformation temperature of 700 °C was also investigated for comparison. Results suggested that the PM Ti-5553 alloy had a better hot workability, with a larger cracking-free processing window, and a lower deformation resistance than the IM counterpart. 45° shear fracture occurred in the PM alloy, compressed at the condition of 600 °C/10 s−1, and edge cracking was observed at the 700 °C/10 s−1. 45° shear fracture was also significant in the IM alloy specimen tested at 700 °C/10 s−1, and all the other IM alloy specimens compressed at 700 °C displayed longitudinal cracking. Moreover, the microscopic cracking observation showed that ductile dimple cracking can be found in the IM alloy, but brittle cleavage fracture was dominant in the cracking surface of PM alloy with a relatively low cracking ductility.

Material Characterization and Electrochemical Properties of Titanium Alloy 5553 Prepared by Selective Laser Melting as Processed and after Abrading and Polishing

“…High-intensity and symmetric diffraction peaks corresponding to the β phase were present at 2θ values (deg) of 39.45 (172,771 counts, 0.52 deg fwhm), 58.54 (10,855 counts, 1.47 deg), and 72.02 (6248 counts, 2.19 deg fwhm). , The weakly intense, symmetric peak at a 2θ value of 35.45 deg (1632 counts, 0.49 deg fwhm) and asymmetric peak at a 2θ value of 85.40 deg (3254 counts, 1.33 deg fwhm) are associated with α and α″ phases, respectively. The peak assignments are based on comparison of diffraction pattern data for this alloy. ,,,, The high intensity of the peak at a 2θ of 39.45 deg indicated that the alloy has a considerable amount of β phase. This is expected because this alloy consists of relatively high atomic levels of the β phase stabilizing elements Mo, V, and Cr.…”

“…Higher-magnification SEM micrographs (secondary and backscattered electron images) for an abraded, polished, and etched specimen (XZ plane) are presented in Figure 6C,D The peak assignments are based on comparison of diffraction pattern data for this alloy. 2,6,47,52,63 The high intensity of the peak at a 2θ of 39.45 deg indicated that the alloy has a considerable amount of β phase. This is expected because this alloy consists of relatively high atomic levels of the β phase stabilizing elements Mo, V, and Cr.…”

“…Titanium alloys (Ti) are widely used in the aerospace (e.g., landing gear) and biomedical (e.g., implants) fields owing to their excellent mechanical properties such as high strength, high fracture resistance, good formability, high temperature properties, and corrosion resistance. − The increased demand for these alloys and the high cost of conventional Ti components prepared using subtractive machining have driven interest in the bottom-up fabrication of intricate Ti parts needed for these applications using additive manufacturing (AM) techniques. − …”