To fabricate W-ZrC composite through reaction sintering at first WC and ZrO2 powders with molar ratio of 3-1 are ball milled, then the green body made from this mixture is sintered. Since reactivity is the main proble...To fabricate W-ZrC composite through reaction sintering at first WC and ZrO2 powders with molar ratio of 3-1 are ball milled, then the green body made from this mixture is sintered. Since reactivity is the main problem in sintering of mironized powders the starting ZrO2 powder is selected in nano size to see whether the reaction improves. The XRD pattern indicates that W-ZrC composite has been formed, although some unreacted compounds still exist and some unwanted components have been created. In the case of using nano powders the amount of unreacted WC and ZrO2 phases and unwanted W2C phase reduces and the reaction progresses better. Additionally by using nano powders the reaction progressed and the mechanical proprieties including density, hardness, Elastic modulus and Flexural strength improved.展开更多
A 30 vol.% ZrCp/W composite has been deformed in compression in the temperature range of 1200-1600℃.Dislocation nucleation mechanism in ZrC particles is discussed by analyzing the harmonious deformation between tungs...A 30 vol.% ZrCp/W composite has been deformed in compression in the temperature range of 1200-1600℃.Dislocation nucleation mechanism in ZrC particles is discussed by analyzing the harmonious deformation between tungsten-matrix and ZrC particles.Thermal activation apparently increases the mobility of screw segments,resulting in the formation of many kinetics jogs and thermodynamics jogs above 1300℃.The formation mechanisms of the dislocation configurations are studied.展开更多
基金Foundation of Shanghai Aerospace Science and TechnologyAid Program for Innovative Group of National University of Defense TechnologyAid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘To fabricate W-ZrC composite through reaction sintering at first WC and ZrO2 powders with molar ratio of 3-1 are ball milled, then the green body made from this mixture is sintered. Since reactivity is the main problem in sintering of mironized powders the starting ZrO2 powder is selected in nano size to see whether the reaction improves. The XRD pattern indicates that W-ZrC composite has been formed, although some unreacted compounds still exist and some unwanted components have been created. In the case of using nano powders the amount of unreacted WC and ZrO2 phases and unwanted W2C phase reduces and the reaction progresses better. Additionally by using nano powders the reaction progressed and the mechanical proprieties including density, hardness, Elastic modulus and Flexural strength improved.
基金Foundation of Shanghai Aerospace Science and TechnologyAid Program for Innovative Group of National University of Defense TechnologyAid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
基金supports from the National Natural Science Foundation of China (No. 50101003)the Scholastic Foundation in Harbin Institute of Technology (No. HIT.2003. 07) are greatly acknowledged
文摘A 30 vol.% ZrCp/W composite has been deformed in compression in the temperature range of 1200-1600℃.Dislocation nucleation mechanism in ZrC particles is discussed by analyzing the harmonious deformation between tungsten-matrix and ZrC particles.Thermal activation apparently increases the mobility of screw segments,resulting in the formation of many kinetics jogs and thermodynamics jogs above 1300℃.The formation mechanisms of the dislocation configurations are studied.
