The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by ...The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by optical microscopy and transmission electron microscopy(TEM).It was characteristic of extremely fine dendrite in the laser melted- resolidified layer and δ-ferrite in bulk form in the center of dendrite.The predominant twin martensite and a little dislocation martensite existed in the dendrite.The thin plate-like M_(213)C_6 carbide precipitated coherently on the twin martensites along their twin plane.There were both austenite rich in W,V and Cr and M_6C carbide in the interdendritic regions.展开更多
Hard coatings are used to improve the wear resistance of metals which largely depends on adhesion between substrate and coating.The wear and friction behavior of uncoated and TiCN-coated D2,M2 and M4 steels were evalu...Hard coatings are used to improve the wear resistance of metals which largely depends on adhesion between substrate and coating.The wear and friction behavior of uncoated and TiCN-coated D2,M2 and M4 steels were evaluated by apin-on-disk test under lubricated conditions.In order to evaluate the influence of lubricant on wear performance,dry friction tests were also performed.The results showed that friction coefficients were very similar for both uncoated and TiCN-coated steels.Under lubricated conditions,the uncoated D2 tool steel exhibited the lowest friction coefficient,but the TiCN-coated D2 steel presented the smallest wear rate.Abrasion was the main wear mechanism in all the tribocouples.Additionally,microhardness measurements were carried out,finding an influence of the steel substrate on the hardness of the coatings.Besides,adhesion test was conducted,suggesting agood adhesion of class 1 between substrates and TiCN coatings.展开更多
文摘The laser melted-resolidified processing on W18Cr4V high speed tool steel has been made us- ing a 1 kW CO_2 continuous wave laser device.The microstructure of the laser melted- resolidified layer has been examined by optical microscopy and transmission electron microscopy(TEM).It was characteristic of extremely fine dendrite in the laser melted- resolidified layer and δ-ferrite in bulk form in the center of dendrite.The predominant twin martensite and a little dislocation martensite existed in the dendrite.The thin plate-like M_(213)C_6 carbide precipitated coherently on the twin martensites along their twin plane.There were both austenite rich in W,V and Cr and M_6C carbide in the interdendritic regions.
基金support of Tecnológico Nacional de México(TNM)(Grant No.5724.16P)
文摘Hard coatings are used to improve the wear resistance of metals which largely depends on adhesion between substrate and coating.The wear and friction behavior of uncoated and TiCN-coated D2,M2 and M4 steels were evaluated by apin-on-disk test under lubricated conditions.In order to evaluate the influence of lubricant on wear performance,dry friction tests were also performed.The results showed that friction coefficients were very similar for both uncoated and TiCN-coated steels.Under lubricated conditions,the uncoated D2 tool steel exhibited the lowest friction coefficient,but the TiCN-coated D2 steel presented the smallest wear rate.Abrasion was the main wear mechanism in all the tribocouples.Additionally,microhardness measurements were carried out,finding an influence of the steel substrate on the hardness of the coatings.Besides,adhesion test was conducted,suggesting agood adhesion of class 1 between substrates and TiCN coatings.
