Heterostructures Enhance Simultaneously Strength and Ductility of a Commercial Titanium Alloy
Heterostructures Enhance Simultaneously Strength and Ductility of a Commercial Titanium Alloy
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DOI：
10.1016/j.actamat.2023.119182
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发表时间：
2023-07
期刊：
影响因子：
9.4
通讯作者：
Di Wu;Mengyuan Hao;Tianlong Zhang;Zhen Wang;Jiang Wang;Guanghui Rao;Li-gang Zhang;Chaoyi Ding;Kechao Zhou;Li-bin Liu;Dong Wang;Yunzhi Wang
中科院分区：
文献类型：
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作者：
Di Wu;Mengyuan Hao;Tianlong Zhang;Zhen Wang;Jiang Wang;Guanghui Rao;Li-gang Zhang;Chaoyi Ding;Kechao Zhou;Li-bin Liu;Dong Wang;Yunzhi Wang
在工业规模上同时提高商用合金的强度和延展性仍然是一项具有挑战性的任务。在这项研究中，我们证明了一种简单的热处理方法，可以在普通钛合金Ti-5Al-5Mo-5V-3Cr-1Zr中获得具有粗晶和超细片层状α析出的异质组织。在计算机模拟的指导下，我们成功地在β相基体中实现了微尺度的浓度调制，通过淬灭由球状初生α相（αp）和β基体组成的双相组织，使α相快速溶解并留下残留浓度。随后，我们采用时效处理，通过激活不同的相变机制，在β基体中形成粗细α和超细α沉淀的精细分散区域。与具有均匀层状组织的商用合金相比，我们生产的异质组织合金的极限抗拉强度提高了6%，伸长率提高了130%。异质组织合金的突出延展性归功于其独特的组织设计，该设计可以防止应变局部化，并允许在粗区和超细α区充分激活位错和孪晶变形。同时，合金的高强度可归因于异质组织应变分配引起的背应力效应增强。我们的研究展示了一种简单而有效的方法，可以在工业规模上在沉淀硬化合金中产生大块异质结构，从而大大提高强度和延展性。
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 αpphase 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.