Powder metallurgy associated to spark plasma sintering was used to elaborate near full-dense samples of 316L austenitic stainless steel with unimodal or bimodal grain size distributions. To this aim, two different precursor powders were employed: a ball-milled one giving rise to ultrafine grains and a coarse one, as-received, for grains with conventional size. Sintered specimens were characterized in mechanical tension and their microstructure was revealed using transmission and scanning electron microscopy. Unimodal ultrafine grained samples show a large yield stress and a low ductility with a breakdown in the Hall-Petch relationship. For bimodal samples, a compromise between yield stress and ductility can be found. These features are then discussed in terms of strain mechanisms, grain size distribution and backstress. It is shown in particular that coarse grains contribute to enhance the ductility of the ultrafine grains matrix by modifying both the strain hardening mechanisms and the stress concentration areas.

与火花等离子烧结相关的粉末冶金用于制作单峰或双峰粒度分布的316L奥氏体不锈钢的近致密样品。为此目的，使用了两种不同的前体粉末：球磨的粉末会产生超细晶粒，而粗粒的粉末会像以前那样用于常规尺寸的晶粒。烧结后的样品具有机械拉伸特性，并通过透射和扫描电子显微镜观察了它们的微观结构。单峰超细晶粒样品显示出大的屈服应力和低延展性，并破坏了霍尔-帕奇关系。对于双峰样品，可以发现屈服应力和延性之间的折衷。然后根据应变机制，晶粒尺寸分布和背应力来讨论这些特征。