The Al3Ti intermetallic reinforced pure Al,Al-13Si and Al-17Cu matrix composites were prepared by casting method.Their microstructures and dry sliding wear behaviors at room temperature and 100℃were particularly inve...The Al3Ti intermetallic reinforced pure Al,Al-13Si and Al-17Cu matrix composites were prepared by casting method.Their microstructures and dry sliding wear behaviors at room temperature and 100℃were particularly investigated.The results indicated that the Al3Ti phases in these composites were all in flaky form.But the aspect ratio of the Al3Ti platelets decreased with the increase of Ti content in the pure Al,Al-Cu and Al-Si matrix composites,in order of effectiveness.The effect of Si on the Al3Ti morphology seemed to be greater than that of Cu.The distributions of the Al3Ti platelets were different in the different matrix composites,leading to different grain refining effects.Except for the sub-wear regime of adhesive wear,the plastic deformation induced wear was a dominant wear mechanism for all of the composites at room temperature and 100℃.Increasing the testing temperature,decreasing the Al3Ti content or the hardness of materials could enhance these two wear mechanisms,and thus increase the wear rate.The Al-Cu matrix composite had the best wear resistance,while the pure Al matrix composite showed the worst for the same Ti content.These differences or changes were attributed to the differences in materials'hardness or the strengthening effects of the Al3Ti platelets.展开更多
The microstructure stability of Al 3Ti/Al alloy prepared by mechanical alloying (MA) was investigated in the simulating environment in which they may be used. The results show that the MA alloy possesses fine microstr...The microstructure stability of Al 3Ti/Al alloy prepared by mechanical alloying (MA) was investigated in the simulating environment in which they may be used. The results show that the MA alloy possesses fine microstructure (the grain size is about 0.5 μm). After cycling loaded followed by heat exposure at 350 ℃ for 24 h, no microstructure coarsening of the alloy occurred, which means that the Al 3Ti/Al alloy behaves good microstructure stability at high temperature. The compression yield strength of the alloy reaches up to 247 MPa at 350 ℃. [展开更多
A novel technique for fabricating TiB_2/Al composites in molten aluminum was introduced. The formation mechanism of brittleAl,Ti particulates up to 30 m in size produced in the composites was studied and a method of e...A novel technique for fabricating TiB_2/Al composites in molten aluminum was introduced. The formation mechanism of brittleAl,Ti particulates up to 30 m in size produced in the composites was studied and a method of eliminating them was proposed. The resultsshow that (l) the brittle Al,Ti particulates are always present in the composites when the molar ratio of Ti to B 'T,:nB is l:2; and (2) theformation of the brittle Al,Ti phase can be avoided entirely from the final product by using a proper 'T,:nB of l:4 in the Ti-B-Al preforms.In the former case, the tensile elongation of the composite is only 4%, much lower than the value of pure aluminum (20%). In the latercase, the tensile elongation of this composite is 10%, higher than the value of the composite with a lot ofAl,Ti (4%), whereas the ultimatetensile stfength of the former is nearly that of the later.展开更多
基金supported by the Development Program for Outstanding Young Teachers in Lanzhou University of Technology
文摘The Al3Ti intermetallic reinforced pure Al,Al-13Si and Al-17Cu matrix composites were prepared by casting method.Their microstructures and dry sliding wear behaviors at room temperature and 100℃were particularly investigated.The results indicated that the Al3Ti phases in these composites were all in flaky form.But the aspect ratio of the Al3Ti platelets decreased with the increase of Ti content in the pure Al,Al-Cu and Al-Si matrix composites,in order of effectiveness.The effect of Si on the Al3Ti morphology seemed to be greater than that of Cu.The distributions of the Al3Ti platelets were different in the different matrix composites,leading to different grain refining effects.Except for the sub-wear regime of adhesive wear,the plastic deformation induced wear was a dominant wear mechanism for all of the composites at room temperature and 100℃.Increasing the testing temperature,decreasing the Al3Ti content or the hardness of materials could enhance these two wear mechanisms,and thus increase the wear rate.The Al-Cu matrix composite had the best wear resistance,while the pure Al matrix composite showed the worst for the same Ti content.These differences or changes were attributed to the differences in materials'hardness or the strengthening effects of the Al3Ti platelets.
文摘The microstructure stability of Al 3Ti/Al alloy prepared by mechanical alloying (MA) was investigated in the simulating environment in which they may be used. The results show that the MA alloy possesses fine microstructure (the grain size is about 0.5 μm). After cycling loaded followed by heat exposure at 350 ℃ for 24 h, no microstructure coarsening of the alloy occurred, which means that the Al 3Ti/Al alloy behaves good microstructure stability at high temperature. The compression yield strength of the alloy reaches up to 247 MPa at 350 ℃. [
文摘A novel technique for fabricating TiB_2/Al composites in molten aluminum was introduced. The formation mechanism of brittleAl,Ti particulates up to 30 m in size produced in the composites was studied and a method of eliminating them was proposed. The resultsshow that (l) the brittle Al,Ti particulates are always present in the composites when the molar ratio of Ti to B 'T,:nB is l:2; and (2) theformation of the brittle Al,Ti phase can be avoided entirely from the final product by using a proper 'T,:nB of l:4 in the Ti-B-Al preforms.In the former case, the tensile elongation of the composite is only 4%, much lower than the value of pure aluminum (20%). In the latercase, the tensile elongation of this composite is 10%, higher than the value of the composite with a lot ofAl,Ti (4%), whereas the ultimatetensile stfength of the former is nearly that of the later.
