混粉电火花加工TaW合金材料表面性能的研究

Surface Properties of Powder Mixed EDM of TaW Alloy Material

该文探讨了高强度、熔点约为3000℃的TaW合金材料进行混粉电火花加工表面性能。通过对同一种材料采用常规电火花(前者)与混粉电火花(后者)加工50 mm的圆面积进行实验对比,前者加工表面粗糙度值为0.542μm,后者可达0.174μm,仅是前者的32%;用MTS纳米压痕仪进行表面压缩弹性模量测试,前者约为280 GPa,后者约为410 GPa,是前者1.46倍;用CJS111A型摩擦磨损实验机进行表面耐磨性能测试,用扫描电镜对磨损表面微细形貌进行观察并分析,加工表面越耐磨则实验机的对磨球磨损率越大,2种加工表面对磨球磨损率是:前者为2.4×10-5mm3/m,而后者为1.4×10-4mm3/m,是前者的5.8倍。研究结果表明:混粉电火花加工比常规电火花加工更能改善零件表面粗糙度、硬度、弹性模量、耐磨等性能,在特种材料的加工领域具有广阔的应用前景。

Two kinds of specimens made of a kind of TaW alloy material with high strength and high melting point about 3 000℃ are processed by a traditional EDM （Electrical Discharge Machining） and a powder mixed EDM separately, and its surface characteristics are tested. After processing, their surfaces have the roughness of 0. 542 μm and 0. 174 μm, and the modulus of elasticity of 280 GPa and 410 GPa, respectively. Moreover, the surface friction-resistance of the specimens are studied on a CJS111A friction and wear tester. The micro-appearances on the frictionized surfaces are observed and analyzed by using a SEM. The test results indicate that the better friction-resistance ability the specimen has, the higher wear rate the frictionized balls display in the test. The wear rates of frictionized ball corresponding to the two processed surfaces are 2.4 × 10^-5 mm^3/m for the traditional EDM and 1.4 × 10^-4 mm^3/m for the powder mixed EDM, which shows the latter is 5.8 times of the former. The results show that the powder mixed EDM is better at improving the surface properties of specimen than the traditional EDM, which means that the technique of powder mixed EDM has a great potential in processing the special material.