JORDAN CONTRERAS, K.S. RAVI CHANDRAN
This study focuses on processing and structure–property correlations in a set of new niobium (Nb) alloys made by spark plasma sintering (SPS). Mechanical properties of common Nb alloys (e.g., C103, Nb-10Hf-1Ti wt pct) are not adequate for high-temperature applications. Alloying Nb with W can increase the elevated temperature strength and creep resistance, although it can negatively affect the low-temperature ductility and toughness. The present study investigated the SPS processing of Nb-5.4Hf-xW-2Ti (at. pct) alloys with varying levels (0–10 at. pct W) of W and oxygen (300–1200 wt ppm) to evaluate the effects of composition and microstructure on fracture toughness. Fracture toughness testing revealed that a maximum fracture toughness (KQ ~ 30 MPa/C214 m) occurs at 5 at. pct W. Surprisingly, alloys with relatively high-oxygen content showed higher fracture toughness levels, compared to the low-oxygen alloys. It is shown that fracture toughness is controlled by the ductile fractures localized near grain boundary regions, caused by HfO2 precipitate-free zones, with grain interiors fracturing by cleavage. The effects of W level, oxygen, and microstructure on fracture toughness and the fracture micro-mechanisms are outlined. The strengthening and fracture toughness behavior of these alloys has been correlated with their composition and microstructure, and through strength and fracture toughness models.
@article{35110ec3-1081-48e5-adbe-383d226ee38e,
title={Processing of Novel Nb-Hf-W-Ti Alloys by Spark Plasma Sintering and Identification of Alloying (W, O) and Microstructural Conditions for Maximizing Fracture Toughness},
author={JORDAN CONTRERAS and K.S. RAVI CHANDRAN},
year={2026},
language={en}
}TY - JOUR TI - Processing of Novel Nb-Hf-W-Ti Alloys by Spark Plasma Sintering and Identification of Alloying (W, O) and Microstructural Conditions for Maximizing Fracture Toughness AU - JORDAN CONTRERAS AU - K.S. RAVI CHANDRAN PY - 2026 LA - en ER -
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This publication, edited by Arthur C. Reardon and published by ASM International®, serves as a comprehensive guide in the field of materials science.