One of the main disadvantages of combustion synthesis of ceramic/metal composite materials is the relatively high level of porosity present in the products. To synthesize TiC/Al composites with a dense structure, this...One of the main disadvantages of combustion synthesis of ceramic/metal composite materials is the relatively high level of porosity present in the products. To synthesize TiC/Al composites with a dense structure, this paper proposes a novel application of an elevated-temperature Al-melt to directly ignite and simultaneously infiltrate Al-Ti-C preform dipped in the melt. The emphasis was placed on the combustion synthesis process and mi-crostructural evolution of the preform in the melt, by a liquid quenching test combined with the measurement of the temperature history of the dipped preform. The results show that the combustion synthesis process of the preform in the elevated-temperature melt involves a series of reactions, and that higher temperature of the melt is favourable for the formation of TiC. The synthesized TiC/Al composites exhibit a dense structure, which is attributed to the infiltration of the melt into the preform.展开更多
The sintering resistance for conductive TiB2 and non-conductive A12O3 as well as empty die during pulse current sintering were investigated in this paper. Equivalent resistances were measured by current and valtage du...The sintering resistance for conductive TiB2 and non-conductive A12O3 as well as empty die during pulse current sintering were investigated in this paper. Equivalent resistances were measured by current and valtage during sintering the conductive and non-conductive materials in the same conditions. It is found that the current paths for conductive are different from those for non-conductive materials. For non-conductive materials, sintering resistances are influenced by powder sizes and heating rates, which indicates that pulse current has some interaction with non-conductive powders. For conductive TiB2 , sintering resistances are influenced by heating rates and ball-milling time, which indicates the effect of powders activated by spark.展开更多
基金Financially supported by the Foundation for Excellent Youth of Wuhan City (No. 20015005028) and the Opening Foundation of State Key Lab of Advanced Technology for Materials Synthesis and Processing.
文摘One of the main disadvantages of combustion synthesis of ceramic/metal composite materials is the relatively high level of porosity present in the products. To synthesize TiC/Al composites with a dense structure, this paper proposes a novel application of an elevated-temperature Al-melt to directly ignite and simultaneously infiltrate Al-Ti-C preform dipped in the melt. The emphasis was placed on the combustion synthesis process and mi-crostructural evolution of the preform in the melt, by a liquid quenching test combined with the measurement of the temperature history of the dipped preform. The results show that the combustion synthesis process of the preform in the elevated-temperature melt involves a series of reactions, and that higher temperature of the melt is favourable for the formation of TiC. The synthesized TiC/Al composites exhibit a dense structure, which is attributed to the infiltration of the melt into the preform.
基金Supported by the Natural Science Foundation of China (59872024) Key Teacher Fund of National Education Ministry and Fund of State Key Lab of Plastic Forming Simulation and Die and Mould Technology(02 -11)
文摘The sintering resistance for conductive TiB2 and non-conductive A12O3 as well as empty die during pulse current sintering were investigated in this paper. Equivalent resistances were measured by current and valtage during sintering the conductive and non-conductive materials in the same conditions. It is found that the current paths for conductive are different from those for non-conductive materials. For non-conductive materials, sintering resistances are influenced by powder sizes and heating rates, which indicates that pulse current has some interaction with non-conductive powders. For conductive TiB2 , sintering resistances are influenced by heating rates and ball-milling time, which indicates the effect of powders activated by spark.
