The NiA1 Cr（Mo） （Hf, Dy） hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigat...The NiA1 Cr（Mo） （Hf, Dy） hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigated. The results reveal that with the addition of Hf and Dy, the Ni2AIHf Heusler phase and NisDy phase form along the NiAI/Cr（Mo） phase boundaries in intercellular region. By the injection casting method, some Ni2AIHf Heusler phase and NisDy phase transform into Hf and Dy solid solutions, respectively. Moreover, the microstructure of the alloy gets good optimization, which can be characterized by the fine interlamellar spacing, high proportion of eutectic cell area and homogeneously distributed fine Ni2AIHf, NisDy, Hf solid solution and Dy solid solutions. Compared with conventional-cast alloy, the room temperature mechanical properties of injection-cast alloy are improved obviously.展开更多
Open-celled porous （TiB2-Al2O3）/NiAl composites were successfully fabricated by using spherical carbamide as space holders via self-propagating high-temperature synthesis （SHS）. Effects of 10Al-3B2O3-3TiO2 conten...Open-celled porous （TiB2-Al2O3）/NiAl composites were successfully fabricated by using spherical carbamide as space holders via self-propagating high-temperature synthesis （SHS）. Effects of 10Al-3B2O3-3TiO2 contents （0-20 wt%） on the pore structures and the quasi-static compressive behaviors of the resultant materials were investigated. The porous （TiBE-Al2O3）/NiAl composites exhibit composite pore structure consisting of homogeneously distributed and interconnected millimeter pores and micropores. The millimeter pores virtually inherit the shape and size of carbamide particles, while the pore size of micropores increases with increasing the 10Al-3BEO3-3TiO2 content. Depending on the volume fraction of the carbamide, the porosity of the porous materials can be easily controlled in a range of 55%-85%. When the porosity is about 72%, the compressive strengths of porous NiAl and porous （TiBE-Al203）/NiAl composite with 15% 10Al-3B2O3-3TiO2 in green compact are 19 and 32 MPa, and the corresponding strains are 2.9% and 5.7%, respectively. Furthermore, the quasi-static compressive behavior of porous （TiB2-AlEO3）/NiAl composites can be estimated by Gibson-Ashby model.展开更多
基金Project(2012M510271) supported by the China Postdoctoral Science FoundationProject(2012BAI18B05) supported by the Five-Year National Key Technology R&D Program during the 12th Five-year Plan of ChinaProject(2011AA030104) supported by the National High Technology Research and Development Program of China
文摘The NiA1 Cr（Mo） （Hf, Dy） hypoeutectic alloys were prepared by conventional casting and injection casting techniques respectively, and their microstructure and room temperature mechanical properties were investigated. The results reveal that with the addition of Hf and Dy, the Ni2AIHf Heusler phase and NisDy phase form along the NiAI/Cr（Mo） phase boundaries in intercellular region. By the injection casting method, some Ni2AIHf Heusler phase and NisDy phase transform into Hf and Dy solid solutions, respectively. Moreover, the microstructure of the alloy gets good optimization, which can be characterized by the fine interlamellar spacing, high proportion of eutectic cell area and homogeneously distributed fine Ni2AIHf, NisDy, Hf solid solution and Dy solid solutions. Compared with conventional-cast alloy, the room temperature mechanical properties of injection-cast alloy are improved obviously.
基金financially supported by the Natural Science Foundation of Shandong Province (No.ZR2014EMM009)the Public School Visiting Fund of Shandong University of Science and Technology
文摘Open-celled porous （TiB2-Al2O3）/NiAl composites were successfully fabricated by using spherical carbamide as space holders via self-propagating high-temperature synthesis （SHS）. Effects of 10Al-3B2O3-3TiO2 contents （0-20 wt%） on the pore structures and the quasi-static compressive behaviors of the resultant materials were investigated. The porous （TiBE-Al2O3）/NiAl composites exhibit composite pore structure consisting of homogeneously distributed and interconnected millimeter pores and micropores. The millimeter pores virtually inherit the shape and size of carbamide particles, while the pore size of micropores increases with increasing the 10Al-3BEO3-3TiO2 content. Depending on the volume fraction of the carbamide, the porosity of the porous materials can be easily controlled in a range of 55%-85%. When the porosity is about 72%, the compressive strengths of porous NiAl and porous （TiBE-Al203）/NiAl composite with 15% 10Al-3B2O3-3TiO2 in green compact are 19 and 32 MPa, and the corresponding strains are 2.9% and 5.7%, respectively. Furthermore, the quasi-static compressive behavior of porous （TiB2-AlEO3）/NiAl composites can be estimated by Gibson-Ashby model.
