The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120...The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W.All laser-treated T20Z samples show two regions with distinctly different microstructural features,as compared with the untreated substrate:dense TiN dendrites and(α+β)-Ti(remelting zone,RMZ),nanoscaleαlaths doped with part of p phase(heat-affected zone,HAZ).The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidification.The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input.In HAZ,the self-quenching effect leads to the formation of nanoscale a laths and the residue ofβphase.Microhardness profile of different regions was measured from the surface to the interior,and the highest microhardness was obtained(~HV 916.8)in the RMZ,as the laser power was set to 240 W.In the present study,we explained various microstructural characteristics induced by laser surface nitriding treatment.展开更多
基金financially supported by the Youth Top Talents Research Project of Hebei Provincial Education Department China(No.BJ2018052)the Natural Science Foundation of Hebei Province of China(Nos.E2019208205 and E2018208126)+3 种基金the National Natural Science Foundation of China(No.51701064)the Science and Technology on Plasma Dynamics Laboratory Fund Project(No.614220206021806)the Key Research and Development Program of Hebei Province(No.19211016D)the Open Foundation of State Key Laboratory of Metastable Materials Science and Technology(Nos.201804 and 201812).
文摘The Ti-20Zr-6.5Al-4V(T20Z,wt%)alloy surface was treated by the process of laser surface nitriding.The evolution of microstructures and microhardness has been investigated by changing the laser power parameter from 120 to 240 W.All laser-treated T20Z samples show two regions with distinctly different microstructural features,as compared with the untreated substrate:dense TiN dendrites and(α+β)-Ti(remelting zone,RMZ),nanoscaleαlaths doped with part of p phase(heat-affected zone,HAZ).The formation of TiN dendrites can be analyzed by a series of complex reactions during the process of melting and solidification.The increase in laser power results in the increase in content of TiN dendrite which is mainly due to the increase in energy input.In HAZ,the self-quenching effect leads to the formation of nanoscale a laths and the residue ofβphase.Microhardness profile of different regions was measured from the surface to the interior,and the highest microhardness was obtained(~HV 916.8)in the RMZ,as the laser power was set to 240 W.In the present study,we explained various microstructural characteristics induced by laser surface nitriding treatment.
