激光定向能量沉积TB6钛合金组织和性能各向异性研究

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Abstract：TB6 titanium alloy was fabricated via laser directed energy deposition （LDED），and the anisotropic characteristics of the microstructure and mechanical properties across different sample cross-sections were systematically investigated，the influence of heat treatmentonanisotropy in microstructure and mechanical property wereanalyzed.Results indicatethattheas-deposited specimenexhibited near-equiaxed grains inthecro-section vertical tothedepositiondirection，whileacolumnar/equiaxedgraincompositestructurewasobserved inthecrosssectionparallel to the deposition direction.Both cross-sections displayeda lamellarbasket weave microstructure， with the α phase in the cross-section vertical to the deposition direction demonstrating a more elongated morphology. This distinct grain structure and α phase configuration endowed the transverse sample with superior microhardness （389.6HV），tensile strength 1337MPa， ，andreducedelongation （2.9%） ，exhibitingpronounced mechanical anisotropy compared to the longitudinal sample.Post heat treatment induced coarsening of the lamellar a phase with reduced width heterogeneity，resulting in a significant decrease in the elongation anisotropy index （IPA） from 99.1 （as-deposited）to 3.2.Fractographicanalysis revealed a transition fromshallw dimples to deep microvoid coalescence， effectively mitigating the mechanical anisotropy.

Keywords： laser directed energy deposition; TB6 alloy; microstructure; heat treatment; anisotropy

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钛合金因其优异的比强度、耐蚀性及高温性能，成为航空航天领域关键承力部件的理想材料。（剩余8128字）