PERSISTENT LIQUID-PHASE SINTERING OF 316L STAINLESS-STEEL

Boron is known to induce persistent liquid phase sintering when added to austenitic stainless steel powders. In the present investigation ad ditions of boron to 316L stainless steel, and their influence on tensi le and impact properties, were investigated. Boron induces two main mi crostructural modifications which strongly influence the mechanical be haviour of the material. One, it increases density, and two, it gives rise to the formation of grain boundary eutectic borides. Whereas an i ncrease in density is positive, the influence of the borides is negati ve because they fracture during plastic straining, reducing both ducti lity and strength. the influence of density and borides on the plastic behaviour of the materials was then analysed in detail with reference to a simple damage model. It is further observed that with the additi on of 0.2w/oB, density shows a noticeable increase and the negative ef fect of borides on the mechanical properties is reduced because of the ir lower amount and discontinuous morphology. This material may theref ore be suitable for technological applications, because of its improve d mechanical properties and because of the presence on the surface of the specimen of a homogeneous layer in which pores are practically abs ent; this promotes good corrosion resistance.