Architecting multiscale heterostructure for exceptional strength-ductility synergy in super duplex stainless steel 2507

A multiscale heterostructure integrating duplex phases, grain size contrast and nanoscale chemical modulations were architected in super duplex stainless steel 2507, achieving a high yield strength of 1112 MPa and ultimate tensile strength of 1411 MPa with a large elongation of 27%. The primary strengthening mechanisms are HDI, dislocation and spinodal decomposition strengthening which were quantitatively assessed. A predictive model for the yield strength evolution with aging time was developed. This study demonstrates a novel strategy for developing high-performance alloys through leveraging multiscale heterostructures to overcome the strength-ductility trade-off.

本研究在2507超级双相不锈钢中构建了集成双相组织、晶粒尺寸差与纳米级化学调制的多尺度异质结构，实现了1112 MPa的高屈服强度、1411 MPa的极限抗拉强度以及27%的优异断后伸长率。研究对HDI强化、位错强化与调幅分解强化这三种主要强化机制进行了定量评估，并建立了屈服强度随时效时间演化的预测模型，提出了一种通过利用多尺度异质结构突破强塑权衡瓶颈的高性能合金开发新策略。