Study On The Relationship Between Microstructure And Properties Of Ni-Al-W Active Composite Materials

In this paper, the different composition ratio of Ni-Al-W active material is microstructure characterized, and its mechanical properties and reactivity tests on the experimental phenomena and analyze data, draw conclusions, obtained Ni-Al-W active fragments material part of the organization and performance relationship.The main research results are as follows:In the preparation of cold spraying Ni-Al-W active composite process, the three did not occur obvious intermetallic reaction and the oxidation reaction; Ni, Al, W are closely contacted and Ni, Al metal particles distributed more homogeneously. Thus, the composite material has good reactivity, the intermetallic reaction:Ni+3Al→NiAl3 can occur at about450 ℃.When the Ni-Al-W active composite material is heated to 600 ℃, a large number of Ni2Al3 formed and as the temperature continues to rise, Ni2Al3 volume increases, NiAl3 phase gradually decreased to disappear; when the temperature reaches 800 ℃,Ni and intermediate phase Ni2Al3 can react to generate NiAl.In the condition of longer heating time and adequate diffusion,within a certain range to increase the content of Ni in the active material of the reaction in favor of Ni Al generation thereby increasing the total energy release,if it contains less amount of Ni then can not generate Ni Al sufficiently.When the Ni-Al-W active composite material was heated to 600 ℃, Al and W react generated Al5 W. When the temperature rises to 690 ℃, W will further participate in the reaction Al4 W. In a certain range increase in the Ni content in the material can inhibit the reaction between Al and W to some extent.Compared with the Ni-Al system,the presence of W in Ni-Al-W active composites will make the unit with the main reaction mass was reduced, releasing energy decreased.The gradually exhibited aggregation effect due to the increase in Ni content of the material will reduce Ni, Al reaction phases effective contact area, making it impossible to fully participate in the reaction in limited heating time results in heat release of the active material.The added W in Ni-Al-W active composite introduces a number of interfaces, and the material in the wrong position during deformation slip by blocking the interface and produce severe stress concentration at the interface, resulting in the strength of Ni-Al-W material is larger than Ni-Al material. And the ratio of the intensity of the different components of the composite material are not sensitive to the strain rate.After the 2000s-1 strain rate dynamic compression tests,Ni, Al and W particles in Ni-Al-W active composite have undergone varying degrees of deformation and the associated microcracks.With the strain rate increases,microcracks generate in the matrix phase and end at Al extension phase at the interface of the two-phase interface.