Nowadays, it is of interest to enhance the strength of metals for light-weight design of nuclear reactor, so the objective of the present study is to improve the mechanical properties of SUS316LN steel through grain refinement. The nanostructured SUS316LN steels were produced by high pressure torsion (HPT) at room temperature. The variations of microstructure and strain-induced martensite transformation during HPT were investigated. The homogeneous nanostructured SUS316LN steel with an average grain size of approximately 40 nm was achieved by HPT for 5 revolutions under a pressure of 5 GPa, which demonstrated extremely high tensile strength (1828 MPa) and high hardness (530 HV). The interstitial nitrogen atoms can reduce the stacking fault energy of the material and also play an important role in interaction with mobile dislocations during HPT. Therefore, compared to SUS316L steel, the formation of the nanograined structure was much faster and the strain-induced martensite transformation was restrained in the HPT-produced SUS316LN steel.

如今，提高核反应堆轻量化设计的金属强度是令人感兴趣的，因此本研究的目的是通过细化晶粒来改善SUS316LN钢的机械性能。纳米结构的SUS316LN钢是在室温下通过高压扭转（HPT）生产的。研究了HPT过程中的微观结构和应变诱发的马氏体相变的变化。通过HPT在5 GPa的压力下旋转5圈可获得平均晶粒尺寸约为40 nm的均质纳米结构SUS316LN钢，这表明其具有极高的拉伸强度（1828 MPa）和高硬度（530 HV）。间隙氮原子可以减少材料的堆垛层错能，并且在HPT过程中与移动位错的相互作用中也起着重要作用。