The novel rapidly solidified TiC/FeAl composite coatings were fabricated by laser cladding on the substrate of 1Cr18Ni9Ti stainless steel, particular emphasis has been placed on the growth morphologies of TiC carbide ...The novel rapidly solidified TiC/FeAl composite coatings were fabricated by laser cladding on the substrate of 1Cr18Ni9Ti stainless steel, particular emphasis has been placed on the growth morphologies of TiC carbide and its growth mechanism under a constant solidification conditions. Results show that the growth morphology of TiC carbide strongly depends upon the nucleation process and mass transportation process of TiC forming elements in laser melt pool. With increasing amount of titanium and carbon in melt pool, the growth morphology of TiC carbide changes from block like to star like and well developed dendrite. As the amount of titanium and carbon increases further, TiC carbide particles are found to be irregular polyhedral block. Although the growth morphologies of TiC are various,their advancing fronts are all faceted, illustrating that TiC carbide grows by the mechanism of lateral ledge growth.展开更多
FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The TiC content was varied from 50% to 80%(volume fraction) and the aluminum content in the binder phase was changed from 40% to ...FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The TiC content was varied from 50% to 80%(volume fraction) and the aluminum content in the binder phase was changed from 40% to 50%(mole fraction). The effects of these compositional changes on the densification process and mechanical properties were studied. The results show that with the increase of TiC content, densities of the composites decrease due to insufficient particle rearrangement aided by (dissolutionreprecipitation) reaction during hot pressing. Closely related with their porosities and defect amount, the hardness and bend strength of the composites show peak values, attaining the highest values with TiC content being 70% and 60%, respectively. Increasing the aluminum content is beneficial to the densification process. But the hardness and bend strength of the composites are reduced to some extent due to the formation of excessive oxides and thermal vacancies.展开更多
FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The effects of TiC content, composition of the binder phase and Ni alloying on the densification process and mechanical propertie...FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The effects of TiC content, composition of the binder phase and Ni alloying on the densification process and mechanical properties of the composites were studied. The results show that the densities of the composites decrease with the increase of TiC content. Closely related with their porosities and flaw densities, the hardness and bend strength of the composites show peak values with the increase of TiC content. Higher content of Al in the binder phase was beneficial to densification, however it deteriorates the mechanical properties of the composites. The addition of Ni significantly improves the densities of the composites by enhancing matter transfer in the binder phase. By alloying with Ni, the mechanical properties of the composites are greatly improved due to the increase of the density, together with solid solution-strengthening the binder phase and promoting ductile fracture of FeAl.展开更多
文摘The novel rapidly solidified TiC/FeAl composite coatings were fabricated by laser cladding on the substrate of 1Cr18Ni9Ti stainless steel, particular emphasis has been placed on the growth morphologies of TiC carbide and its growth mechanism under a constant solidification conditions. Results show that the growth morphology of TiC carbide strongly depends upon the nucleation process and mass transportation process of TiC forming elements in laser melt pool. With increasing amount of titanium and carbon in melt pool, the growth morphology of TiC carbide changes from block like to star like and well developed dendrite. As the amount of titanium and carbon increases further, TiC carbide particles are found to be irregular polyhedral block. Although the growth morphologies of TiC are various,their advancing fronts are all faceted, illustrating that TiC carbide grows by the mechanism of lateral ledge growth.
文摘FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The TiC content was varied from 50% to 80%(volume fraction) and the aluminum content in the binder phase was changed from 40% to 50%(mole fraction). The effects of these compositional changes on the densification process and mechanical properties were studied. The results show that with the increase of TiC content, densities of the composites decrease due to insufficient particle rearrangement aided by (dissolutionreprecipitation) reaction during hot pressing. Closely related with their porosities and defect amount, the hardness and bend strength of the composites show peak values, attaining the highest values with TiC content being 70% and 60%, respectively. Increasing the aluminum content is beneficial to the densification process. But the hardness and bend strength of the composites are reduced to some extent due to the formation of excessive oxides and thermal vacancies.
基金Project(96JJY2009) supported by the Natural Science Foundation of Hunan Province
文摘FeAl/TiC composites were fabricated by reactive hot pressing blended elemental powders. The effects of TiC content, composition of the binder phase and Ni alloying on the densification process and mechanical properties of the composites were studied. The results show that the densities of the composites decrease with the increase of TiC content. Closely related with their porosities and flaw densities, the hardness and bend strength of the composites show peak values with the increase of TiC content. Higher content of Al in the binder phase was beneficial to densification, however it deteriorates the mechanical properties of the composites. The addition of Ni significantly improves the densities of the composites by enhancing matter transfer in the binder phase. By alloying with Ni, the mechanical properties of the composites are greatly improved due to the increase of the density, together with solid solution-strengthening the binder phase and promoting ductile fracture of FeAl.
