To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder ...To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder as the cladding material.The microstructure,phase structure and properties of the coatings were analyzed by SEM,XRD,EPMA,TEM,hardness tester and fretting wear meter.It was observed that the outer ring of the network-like structure was mainly TiB strengthening phase,while the inner ring was α-Ti grain,and the interface between TiB and Ti matrix was very clean and had a consistent orientation relationship.The hardness of the cladding layer with network-like structure gradually decreased from the surface toward the interface,but the average hardness was nearly two times that of the substrate.In the fretting wear test,it was found that the wear resistance of the cladding layer with network-like structure was larger than that of the substrate under low load(40 N).The results revealed that the hardness and fretting wear resistance of the titanium-based composite coating could be improved by the introduction of network-like structure.展开更多
Fe Co Cr Ni Mn high-entropy alloys were produced by mechanical alloying（MA） and vacuum hot pressing sintering（VHPS）. Results showed that the nano-crystalline alloy powders were obtained by MA and the corresponding...Fe Co Cr Ni Mn high-entropy alloys were produced by mechanical alloying（MA） and vacuum hot pressing sintering（VHPS）. Results showed that the nano-crystalline alloy powders were obtained by MA and the corresponding phase structures were composed of FCC matrices and low amounts of BCC and amorphous phases. After VHPS, the BCC phases almost disappeared, simultaneously with the precipitation of σ phases and M23C6 carbides. An increase of sintering temperature resulted in grain growth of the precipitated phases. As the sintering temperature was increased from 700 to 1000℃, the strain-to-failure of the alloys rose from 4.4% to 38.2%, whereas the yield strength decreased from 1682 to 774 MPa. The bulk FeCoCrNiMn HEAs, consolidated by VHPS at 800℃ and 900℃ for 1 h, showed relatively good combination of strength and ductility.展开更多
基金Projects(2019J01813,2018J01557) supported by the Natural Science Foundation of Fujian Province,ChinaProject(2018H0031) supported by the Guiding Science Program of Fujian Province,ChinaProject(2018GP2002) supported by the Science and Technology Program of Putian City,China
文摘To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process,network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB2 powder as the cladding material.The microstructure,phase structure and properties of the coatings were analyzed by SEM,XRD,EPMA,TEM,hardness tester and fretting wear meter.It was observed that the outer ring of the network-like structure was mainly TiB strengthening phase,while the inner ring was α-Ti grain,and the interface between TiB and Ti matrix was very clean and had a consistent orientation relationship.The hardness of the cladding layer with network-like structure gradually decreased from the surface toward the interface,but the average hardness was nearly two times that of the substrate.In the fretting wear test,it was found that the wear resistance of the cladding layer with network-like structure was larger than that of the substrate under low load(40 N).The results revealed that the hardness and fretting wear resistance of the titanium-based composite coating could be improved by the introduction of network-like structure.
基金Project(2014H6005) supported by the Major Industry-Academy Cooperation Program of Fujian Province,ChinaProject(LY17E050003) supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(2016PY015) supported by the Cultivation Foundation of Taizhou University,China
文摘Fe Co Cr Ni Mn high-entropy alloys were produced by mechanical alloying（MA） and vacuum hot pressing sintering（VHPS）. Results showed that the nano-crystalline alloy powders were obtained by MA and the corresponding phase structures were composed of FCC matrices and low amounts of BCC and amorphous phases. After VHPS, the BCC phases almost disappeared, simultaneously with the precipitation of σ phases and M23C6 carbides. An increase of sintering temperature resulted in grain growth of the precipitated phases. As the sintering temperature was increased from 700 to 1000℃, the strain-to-failure of the alloys rose from 4.4% to 38.2%, whereas the yield strength decreased from 1682 to 774 MPa. The bulk FeCoCrNiMn HEAs, consolidated by VHPS at 800℃ and 900℃ for 1 h, showed relatively good combination of strength and ductility.
