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In-situ intragranular TiB modulation for enhanced strength-ductility synergy in TiB/Ti6Al4V composites fabricated by laser directed energy deposition
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DOI:10.1080/17452759.2026.2710531.png)
Abstract
En 中文
Programming TiB reinforcement patterns in laser directed energy deposited titanium matrix composites (TMCs) holds considerable promise for enhancing mechanical properties, but it remains challenging due to unsatisfactory cooling. This study realised in-situ modulation of TiB distributions, including prior β-Ti grain interiors and boundaries in 0.1 wt.% B-modified TiB/Ti6Al4V composites manufactured under low laser energy density (LED) parameters (25.0 J/mm²–40.4 J/mm²) through laser power modulation. Unique intragranular TiB (IG-TiB) was assembled by multiple fine whiskers into cage-like structures. The composites modified by IG-TiB and grain boundary TiB (GB-TiB) displayed excellent strength-ductility synergy at room temperature, particularly at 750 W, which achieved an ultimate tensile strength of 1126.1 MPa and elongation to fracture of 10.6%. In-situ analysis revealed that GB-TiB caused significant local strain concentration at the prior β-Ti grain boundaries and ultimately led to intergranular failure. However, the dispersed IG-TiB retarded strain localisation in single areas by inducing cooperative deformation across multiple soft-oriented α colonies. Improved intergranular bonding and reasonable multiregional-distributed strain partitioning synergistically facilitated TMCs ductility. Strength enhancement was attributed to grain refinement, cooperative load-transfer effects by IG-TiB/GB-TiB, and Orowan strengthening mechanisms. This work proposed new insights into customising intragranular and grain boundary TiB patterns in additively manufactured TMCs.
Keywords:
Laser directed energy deposition
titanium matrix composites
intragranular TiB
strength-ductility synergy
Journal
IF:
8.8
Papers:
1.0K
Citations:
4.9K
