| China is the world's most abundant country in tungsten resources,but also the world's largest tungsten producer and exporter.China's tungsten ore processes many characteristics which involve the rich resources,the comprehensive type of deposits,and a variety of mineralization.Because of its unique physical and chemical properties,it is widely used in military,electronics,metallurgy,petroleum,aerospace and other important industrial fields acted as a refractory rare metal.As an important product of the tungsten industry,tungsten carbide can generally be obtained by carbothermal reduction.Tungsten carbide powder is generally used for cemented carbide production materials,and can also be used to prepare cutting tools,wear-resistant materials,etc.Owing to high atomic number of tungsten contained in tungsten carbide,it can be used for shielding rays.In recent years,some application studies have been carried out on the field of shielded radiation tungsten carbide.Generally,the advantages of high strength,high hardness,large elastic modulus and chemical stability are owned by WC.Functional materials with excellent mechanical properties have been prepared by using a reinforced phase of composite based on it by domestic and foreign researchers.At the same time,the aluminum matrix composites have the characteristics of light weight and high specific strength.It has become the hotspot that the tungsten carbide containing high atomic number is used as the hard phase reinforced aluminum matrix composite material,which makes the material have the effect of ray shielding and has excellent mechanical properties.In the traditional preparation process,the uniform distribution of the enhanced phase in the matrix is the goal which is always pursued.However,increasingly studies reveal that although reinforced phase homogeneous distribution of metal matrix composites are equipped with many excellent properties compared with a single metal material,it is difficult to obtain the desired enhancement effect.The phase of the distribution of the work has been proceeded to optimize by people from the 20 th century,so that the effect of enhanced phase can better improve the comprehensive mechanical properties of composite materials.The sintered samples were prepared by cold pressing and then vacuum pressing and sintering,The phase structure and mechanical properties of the samples before and after sintering were tested and analyzed.The test results are as follows: After the hot pressing,the densities of the samples were improved from 86.2% to 98.61%.Sintering pressure on the composite material density also have a greater impact,but the pressure above 35 MPa,the sample density increase is not.When the temperature higher than the melting point of aluminum matrix 650 ?,the phenomenon of aluminizing was occurred above the mold.phase analysis of the sample before and after sintering showed that the interface reaction was not obvious,within the increase of temperature the interface reaction product appeared,and the higher the temperature the higher the reaction product.The surface morphology of the composites was analyzed by metallographic microscope and scanning electron microscope.It was found that the reinforced phase of the composites was arranged in the matrix,and no other elements were found in the micro-element surface scanning.The gray phase was WAl12.Vickers hardness indicates that the sample increases with the temperature,the hardness of the composite material from 42 to 79.However,when the temperature reaches 660 ?,the sample Vickers hardness is too high,but not conducive to follow-up processing.Sintering pressure on the composite material density also has a greater impact.But when the pressure reaches above 35 MPa,it occurs that the density of the sample is not significantly improved.The compressive strength indicates that the strength of the samples is increased in different degrees due to the pressure of the vacuum sintering and the sintering. |
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