To gain a better understanding of thixoforging for the Al_(2)O_(3)-37%Al composite,its mechanical behavior in the pseudo-semi-solid state was studied by isothermal compression tests.The results show that the values of...To gain a better understanding of thixoforging for the Al_(2)O_(3)-37%Al composite,its mechanical behavior in the pseudo-semi-solid state was studied by isothermal compression tests.The results show that the values of peak stress obviously decrease with increasing temperature and decreasing strain rate.The compressive true stress-strain curves of the Al_(2)O_(3)-37%Al composite can be divided into four stages.They are rapidly ascending,decreasing,steady and slowly ascending.Moreover,the main deformation mechanism controlling deformation of the composite in the pseudo-semi-solid state is the sliding or rotary movement between solid particles.展开更多
A new technology for ceramics matrix composites-ceramics matrix composite thixoforming in pseudo-semi-solid state based on semi-solid metal process and powder metallurgy technology were proposed. The rheological behav...A new technology for ceramics matrix composites-ceramics matrix composite thixoforming in pseudo-semi-solid state based on semi-solid metal process and powder metallurgy technology were proposed. The rheological behavior of Al2O 3n/Alμ composite was studied by isothermal compression in pseudo-semi-solid state. The variation rules of the true stress-true strain, rheological behavior and the influencing factors were also analyzed. The results show that the flow stress decreases evidently with the increasing pseudo-semi-solid temperature, and that the trend of the true stress-true strain curve of the composite in pseudo-semi-solid state can be divided into four stages: increase, decline, re-increase and re-decline.展开更多
A new technology thixo-die-forging of the composite in pseudo-semi-solid state was proposed based on the powder metallurgy technology combing with semi-solid metal process, and the cup shells with Al/Al2O3 composite w...A new technology thixo-die-forging of the composite in pseudo-semi-solid state was proposed based on the powder metallurgy technology combing with semi-solid metal process, and the cup shells with Al/Al2O3 composite was prepared successfully. The metallographic analysis and performance test show that the microstructure of parts is dense and mechanical properties axe excellent with the volume fraction of Al is 37%. The bend strength and fracture toughness of the composite are about 570- 690 MPa and 8.5-16.8 MPa·m^1/2, respectively. Comparing with reaction in situ and high temperature oxidation technologies the bending strength and fracture toughness are improved greatly. At the same time, it shows that the technology parameters have great influences on the properties. So it is feasible to prepare metal/ceramics composites by the proposed technology.展开更多
基金Project(50705018)supported by the National Natural Science Foundation of ChinaProject(20070420847)supported by the Postdoctor Foundation of ChinaProject(LBH-Z07140)supported by the Postdoctor Foundation of Heilongjiang。
文摘To gain a better understanding of thixoforging for the Al_(2)O_(3)-37%Al composite,its mechanical behavior in the pseudo-semi-solid state was studied by isothermal compression tests.The results show that the values of peak stress obviously decrease with increasing temperature and decreasing strain rate.The compressive true stress-strain curves of the Al_(2)O_(3)-37%Al composite can be divided into four stages.They are rapidly ascending,decreasing,steady and slowly ascending.Moreover,the main deformation mechanism controlling deformation of the composite in the pseudo-semi-solid state is the sliding or rotary movement between solid particles.
文摘A new technology for ceramics matrix composites-ceramics matrix composite thixoforming in pseudo-semi-solid state based on semi-solid metal process and powder metallurgy technology were proposed. The rheological behavior of Al2O 3n/Alμ composite was studied by isothermal compression in pseudo-semi-solid state. The variation rules of the true stress-true strain, rheological behavior and the influencing factors were also analyzed. The results show that the flow stress decreases evidently with the increasing pseudo-semi-solid temperature, and that the trend of the true stress-true strain curve of the composite in pseudo-semi-solid state can be divided into four stages: increase, decline, re-increase and re-decline.
基金supported by National Natural Science Foundation of China(No50705018)Postdoctoral Foundation of China (No20070420847)
文摘A new technology thixo-die-forging of the composite in pseudo-semi-solid state was proposed based on the powder metallurgy technology combing with semi-solid metal process, and the cup shells with Al/Al2O3 composite was prepared successfully. The metallographic analysis and performance test show that the microstructure of parts is dense and mechanical properties axe excellent with the volume fraction of Al is 37%. The bend strength and fracture toughness of the composite are about 570- 690 MPa and 8.5-16.8 MPa·m^1/2, respectively. Comparing with reaction in situ and high temperature oxidation technologies the bending strength and fracture toughness are improved greatly. At the same time, it shows that the technology parameters have great influences on the properties. So it is feasible to prepare metal/ceramics composites by the proposed technology.
