For most engineering materials, the properties of strength and ductility are mutually exclusive, and no process has been reported to enhance the strength and ductility of steels by carbon. Nevertheless, the quenching and partitioning (Q&P) process, which was originally proposed in 2003, is a promising method for the fabrication of carbon-alloyed steels with high strength and ductility. In this work, we show that the development of a composite-like microstructure in steels during Q&P process can enhance the strength and ductility of Fe–Mn–Si–Nb–C steels containing 0.2–0.4 wt% C. In contrast to the traditional quenching and tempering process, the novel Q&P (or Quenching-Partitioning-Tempering) process can link strength enhancement, which is conferred by the hard martensite phase, with ductility enhancement, which is conferred by the retained soft austenite fraction. The origin of such different effects of carbon is revealed by the microstructural characterization.

对于大多数工程材料而言，强度和延展性是互斥的，没有报道过用碳来增强钢的强度和延展性的工艺。尽管如此，最初于2003年提出的淬火和分配（Q＆P）工艺是一种具有高强度和延展性的碳合金钢制造的有前途的方法。在这项工作中，我们表明，在Q＆P过程中，钢中类似复合组织的发展可以增强含0.2-0.4 wt％C的Fe-Mn-Si-Nb-C钢的强度和延展性。淬火和回火过程中，新颖的Q＆P（或淬火-分区-回火）过程可以将强度增强（由硬马氏体相赋予）与延性增强相结合，这是由残留的软奥氏体部分赋予的。碳的这种不同作用的起源通过微观结构表征得以揭示。