TY - JOUR
T1 - Heterostructures enhance simultaneously strength and ductility of a commercial titanium alloy
AU - Wu, Di
AU - Hao, Mengyuan
AU - Zhang, Tianlong
AU - Wang, Zhen
AU - Wang, Jiang
AU - Rao, Guanghui
AU - Zhang, Ligang
AU - Ding, Chaoyi
AU - Zhou, Kechao
AU - Liu, Libin
AU - Wang, Dong
AU - Wang, Yunzhi
PY - 2023/9/15
Y1 - 2023/9/15
N2 - Enhancing both strength and ductility simultaneously in commercial alloys at an industrial scale remains a challenging task. In this study, we have demonstrated a simple heat treatment method to achieve a heterostructure with coarse and ultra-fine lamellar α precipitates in a common titanium alloy, Ti-5Al-5Mo-5V-3Cr-1Zr. Guided by computer simulations, we successfully attained microscale concentration modulations in the β-phase matrix using up-quenching of a duplex microstructure consisting of a globular primary α phase (αp) and β matrix to dissolve the αp phase rapidly and leave residual concentrations. We subsequently applied aging treatments to create finely dispersed regions of coarse and ultra-fine α precipitates embedded in the β matrix by activating different phase transformation mechanisms. Compared to the commercial alloy that has a homogeneous lamellar structure, the heterostructured alloy we produced exhibits a 6% increase in ultimate tensile strength and a remarkable 130% increase in elongation. The outstanding ductility of the heterostructured alloy is attributable to its unique microstructure design, which prevents strain localization and allows full activation of dislocation and twin deformations in the coarse and ultra-fine α regions. Meanwhile, the high strength of the alloy can be attributed to the enhanced back stress effect induced by strain partitioning of the heterostructure. Our study demonstrates a simple and effective method for creating bulk heterostructures in precipitation-hardened alloys at an industrial scale, leading to substantially improved strength and ductility. © 2023 Acta Materialia Inc. Published by Elsevier Ltd.
AB - Enhancing both strength and ductility simultaneously in commercial alloys at an industrial scale remains a challenging task. In this study, we have demonstrated a simple heat treatment method to achieve a heterostructure with coarse and ultra-fine lamellar α precipitates in a common titanium alloy, Ti-5Al-5Mo-5V-3Cr-1Zr. Guided by computer simulations, we successfully attained microscale concentration modulations in the β-phase matrix using up-quenching of a duplex microstructure consisting of a globular primary α phase (αp) and β matrix to dissolve the αp phase rapidly and leave residual concentrations. We subsequently applied aging treatments to create finely dispersed regions of coarse and ultra-fine α precipitates embedded in the β matrix by activating different phase transformation mechanisms. Compared to the commercial alloy that has a homogeneous lamellar structure, the heterostructured alloy we produced exhibits a 6% increase in ultimate tensile strength and a remarkable 130% increase in elongation. The outstanding ductility of the heterostructured alloy is attributable to its unique microstructure design, which prevents strain localization and allows full activation of dislocation and twin deformations in the coarse and ultra-fine α regions. Meanwhile, the high strength of the alloy can be attributed to the enhanced back stress effect induced by strain partitioning of the heterostructure. Our study demonstrates a simple and effective method for creating bulk heterostructures in precipitation-hardened alloys at an industrial scale, leading to substantially improved strength and ductility. © 2023 Acta Materialia Inc. Published by Elsevier Ltd.
KW - Heat treatment
KW - Metastable β titanium alloy
KW - Precipitation
KW - Pseudo-spinodal decomposition
KW - Strength and ductility
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U2 - 10.1016/j.actamat.2023.119182
DO - 10.1016/j.actamat.2023.119182
M3 - RGC 21 - Publication in refereed journal
SN - 1359-6454
VL - 257
JO - Acta Materialia
JF - Acta Materialia
M1 - 119182
ER -