다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Dynamic and post-dynamic recrystallization under hot, cold and severe plastic deformation conditions

Alloy design based on single-principal-element systems has approached its limit for performance enhancements. A substantial increase in strength up to gigapascal levels typically causes the premature failure of materials with reduced ductility. Here, we report a strategy to break this trade-off by controllably introducing high-density ductile multicomponent intermetallic nanoparticles (MCINPs) in complex alloy systems. Distinct from the intermetallic-induced embrittlement under conventional wisdom, such MCINP-strengthened alloys exhibit superior strengths of 1.5 gigapascals and ductility as high as 50% in tension at ambient temperature. The plastic instability, a major concern for high-strength materials, can be completely eliminated by generating a distinctive multistage work-hardening behavior, resulting from pronounced dislocation activities and deformation-induced microbands. This MCINP strategy offers a paradigm to develop next-generation materials for structural applications.

Multicomponent intermetallic nanoparticles and superb mechanical behaviors of complex alloys

The effect of morphology on the stability of retained austenite in a quenched and partitioned steel

Austenite stability and deformation behavior in a cold-rolled transformation-induced plasticity steel with medium manganese content

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

http://science.sciencemag.org/content/sci/early/2017/08/23/science.aan0177.full.pdf

Haiwen Luo

Papers

High dislocation density–induced large ductility in deformed and partitioned steels

Experimental and numerical analysis on formation of stable austenite during the intercritical annealing of 5Mn steel

Effect of intercritical annealing on the Lüders strains of medium Mn transformation-induced plasticity steels

Nanoindentation investigation on the mechanical stability of individual austenite grains in a medium-Mn transformation-induced plasticity steel

Experimental investigation on a novel medium Mn steel combining transformation-induced plasticity and twinning-induced plasticity effects