CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractu...CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.展开更多
Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted expl...Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one展开更多
Direct explosive compaction and sintering of a mixture of Ti-30Al-2Mn(wt%)and Ti-38Al-2Mn(wt%) intermetallic compound powders were carried out.Microstructure and phase characteristics of the alloys were analysed by TE...Direct explosive compaction and sintering of a mixture of Ti-30Al-2Mn(wt%)and Ti-38Al-2Mn(wt%) intermetallic compound powders were carried out.Microstructure and phase characteristics of the alloys were analysed by TEM,SEM,X-ray diffractometry and optical microscopy.The results showed that the rel- ative density of the samples which were explosive-compacted and sintered reached 99.90%,and fine grain structure was obtained.Through the explosive-compacting and then sintering at 1373 K in argon atmos- phere,mutual diffusion between Ti-30Al-2Mn particles and Ti-38Al-2Mn particles took place and TiAl phase was formed in the alloy.TiAl based alloys prepared by high-energy ball-milling powders had much fi- ner grain size than those prepared by general ball-milling powdeis.展开更多
Observations of microstructure of explosive compacts made of Al or Al-Li alloy powders by atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical and scanning electron microscopes.The rsults...Observations of microstructure of explosive compacts made of Al or Al-Li alloy powders by atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical and scanning electron microscopes.The rsults indicate that super quality explosive compact can only be obtained by powders of which the thickness of the oxide layer is less than 30 nm.展开更多
Use of mechanically alloying for preparation of Ti-35at.%Al results in significant reduction in crystal size, so the ductility of alloy can be improved Consolidation of Mechanically alloyed γ -TiAl is difficult becau...Use of mechanically alloying for preparation of Ti-35at.%Al results in significant reduction in crystal size, so the ductility of alloy can be improved Consolidation of Mechanically alloyed γ -TiAl is difficult because of its poor workability. The present paper will discuss recent studies on consolidation behavior by using different methods, such as explosive compaction, hot isostatic pressing, and rapid omnidirectional compaction, etc.. The microstructure and property of the samples are evaluated.展开更多
文摘CuCr alloys are prepared by mechanical alloying and explosive compaction. After we have studied their structure and flaws, the results show that the CuCr alloys have definite strength and toughness, while their fractured surface displays ductile characteristics. In the metallurgical structure, CuCr alloys are composed of two phases of uniform distribution; the SEM morphology is like thin strips with an end arrangement that is bonded to each other and the two-phase distribution of CuCr alloys is more homogenous. It is in only in a very small zone that formation of Cu-rich and Cr-rich phases take place. The flaws of the compaction samples are mainly central-holes and cracks.
文摘Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one
基金Project was supported by National Advanced Materials Committee of China.
文摘Direct explosive compaction and sintering of a mixture of Ti-30Al-2Mn(wt%)and Ti-38Al-2Mn(wt%) intermetallic compound powders were carried out.Microstructure and phase characteristics of the alloys were analysed by TEM,SEM,X-ray diffractometry and optical microscopy.The results showed that the rel- ative density of the samples which were explosive-compacted and sintered reached 99.90%,and fine grain structure was obtained.Through the explosive-compacting and then sintering at 1373 K in argon atmos- phere,mutual diffusion between Ti-30Al-2Mn particles and Ti-38Al-2Mn particles took place and TiAl phase was formed in the alloy.TiAl based alloys prepared by high-energy ball-milling powders had much fi- ner grain size than those prepared by general ball-milling powdeis.
文摘Observations of microstructure of explosive compacts made of Al or Al-Li alloy powders by atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical and scanning electron microscopes.The rsults indicate that super quality explosive compact can only be obtained by powders of which the thickness of the oxide layer is less than 30 nm.
文摘Use of mechanically alloying for preparation of Ti-35at.%Al results in significant reduction in crystal size, so the ductility of alloy can be improved Consolidation of Mechanically alloyed γ -TiAl is difficult because of its poor workability. The present paper will discuss recent studies on consolidation behavior by using different methods, such as explosive compaction, hot isostatic pressing, and rapid omnidirectional compaction, etc.. The microstructure and property of the samples are evaluated.
