Study Of Influence Of Ti~+Pre-implantation On Structure And Properties Of Elevated Temperature N~+Implanted Layers On316L Stainless Steel

A superficial strengthened layer is one of the key factors restricting the wide application ofion implantation. A hybrid surface modification technique of steel including titaniumpre-implantation and nitrogen ion implantation at elevated temperature, which can greatlyimprove both the depth and hardness of the alloyed surface layer of ion implantation, is proposedon the basis of the study of titanium implantation and nitrogen ion implantation at elevatedtemperature. The effect of the dose of titanium pre-implantation and the dose of low-energynitrogen implantation on the surface modified layers of316L stainless steels obtained by thehybrid surface modification was investigated. And the results as follows were found:(1) Both hardness and wear resistance are increased with increasing dose up to1.0×1018ions/cm2, but they are decreased when the dose is further increased. The surface hardness andwear resistance of316L steels modified by titanium implantation at dose of1.0×1018ions/cm2are increased by52%and21%respectively compared with those of unimplanted substrate.(2) The diffusion of nitrogen atoms during medium-energy nitrogen ion implantation at300℃can be enhanced by titaniumion pre-implantation, which can increase the depth of the alloyedlayer and reduce the gradient of the implanted element. With the increasing of titaniumpre-implantation dose, surface hardness and wear resistance of modified steel are first increased,then they are decreased when the dose is further increased. The surface hardness and wearresistance of the implanted layers obtained by the hybrid surface modification are increased by37.5%and4.2%respectively compared with those of nitrogen implanted layers. Themodification layer possesses the best wear resistance when the samples are pre-implanted bytitanium at dose of1.0×1018ions/cm2, and it is increased by16.7%compared to that of nitrogenimplanted layers.(3) The depth of the alloyed layer, nano hardness and wear resistance of modified samplesare improved when the samples are implanted titanium with a suitable dose. When the titaniumpre-implantation dose is1.0×1017ions/cm2, the depth of the alloyed layer, nano hardness andwear resistance of modified layers obtained by the hybrid surface modification are improvedsignificantly, and they can be increased by66.7%,29.9%and29.9%respectively comparedwith those of nitrogen implanted layers. (4) The depth of alloyed layer, surface hardness and wear resistance of compound modifiedlayers obtained by the hybrid surface modification are higher than those of nitrogen implantedlayers, and they are increased with the increasing of nitrogen implantation dose. With theincreasing of nitrogen implantation dose, the treatment of titanium ion pre-implantation canpromote the nitrogen atoms to diffuse deeper. When the nitrogen implantation dose is2.0×1019ions/cm2, the depth of the alloyed layer of compound modified layers is increased by68.3%compared with that nitrogen implanted layers.