The Powder Material Ultrasonic Compaction Development And Testing Of New Process Units

Along with the development of material sciences, people pay more and more attention to the advantage of Powder Metallurgy (P/M) in the preparation, manufacture and deformation of advanced and refractory metals. The intensity and toughness is weaker, compared with the compaction metals, because the porosity of P/M production. Therefore, it is a research focus that improves the density of P/M production and sequentially improves the physics and mechanical property. Aiming at this problem, a novel method of ultrasonic powder compaction is presented and the main researches in the paper are as followed:(1) With the investigation on the character of impedance of ultrasonic transducer and the work condition, an ultrasonic powder compaction device with a novel method which protects ultrasonic transducer and loads prestressing force was designed. According to the method of finite element analysis, the relationship between the size and natural frequency of press stick were investigated and the size of press stick which matches the resonance frequency of ultrasonic transducer was decided.(2) According to the mechanical of plasticity forming of powder and the antifriction effect of ultrasonic vibration, the process of ultrasonic powder compaction was accomplished with finite element software. The results show that the friction reduction caused by ultrasonic vibration made the distribution of equivalent stress in powder compacts more uniform, decrease the breakage caused by the uneven of internal stress when powder compact was ejected, the loss of pressure was reduced and the density and the uniformity improved.(3) The iron powder was used as raw material and the ultrasonic powder compaction was investigated and the relationship between density of compact and pressure under the condition of ultrasonic compaction and conventional compaction was compared. The results show that the most improvement of density of ultrasonic compaction is 0.3g/cm3 in the condition of 500～700MPa, the difference of density along axis direction decreases from 0.76g/cm3 to 0.6g/cm3, the porosity decreases by 4.3%.It shows that the density and the uniformity of powder compact were improved under ultrasonic compaction, the loss of press was decreased and the quality and the mechanical property were improved.In addition, the technique and the equipment were investigated in this paper is available to other materials.