Study On The Explosive Sintering Process And Properties Of Nano-aluminum Powders

The explosive sintering process has the advantages of low cost and high production capacity,so its application in the nanometer block material has become a hotspot.Among them,nano-block aluminum material has been an important research object of the explosion sintering process due to its excellent properties of low density,high hardness and strong corrosion resistance.So the nano-aluminum powder was selected as the raw material,and its explosive sintering process was studied by a series of theories and experiments.For the theories,in the paper,the mechanism of forming the nano-aluminum bars by explosive sintering was analyzed in detail.Firstly,the macroscopic and microscopic mechanism of explosion sintering process was studied.Next,the numerical calculation of the shock wave in the process of load was studied.Then the thermodynamic changes of nano-aluminum powders in shock compaction were analyzed.At last,the phenomena such as the Mach hole and the crack in the previous experiments were made theoretical explanations.So the theoretical guidance for subsequent experimental study was also provided.For the experiments,in the paper,the factors such as the experimental device,explosive detonation velocity and the initial density of nano-aluminum powders were studied.Firstly,the explosive sintering device of single layer and double layer pipe was compared.And then the influence of the pressure relief hole opened at the bottom of the end plug was also studied.In addition,the detonation velocity of the explosive was adjusted by changing the proportion of ammonium nitrate explosives and wood powders.At last,the initial density of nano-aluminum powders was adjusted by changing the pressure of filling.And the conclusions were summarized into the following four aspects.Firstly,the explosive sintering device with double layer pipe showed better than the sintering device with single layer pipe for the forming of aluminum bars.Secondly,the cast hole at the bottom of the aluminum bar could reduce or even eliminate when opening the pressure relief hole with appropriate size.Thirdly,the Mach hole would turn up under the excessive detonation velocity,while the sintering process would be hindered under the insufficient detonation velocity.The perfect nano-aluminum bars with better forming capability and higher hardness could be made only when the detonation velocity was 2158m/s.At last,the compactness of the aluminum bars would be higher with the increasing initial density of nano-aluminum powders.But the changes tended to be gentle when the initial density exceeded to 48.5%.And it could lead to excessive welding between the drivepipe and the aluminum bar.All of the above conclusions can make some guiding significance for the following studies of the explosive sintering process.