The Preparation Of The Porous TiZrNb And The Study On The Factors Effecting On The Porosity

In this paper, powder metallurgy technique was employed to prepare porous TiZrNb alloy. The pore characteristics were investigated by the image analysis technology, then the factors effecting on the pore were studied. Optical microscope, Scanning electron microscope (SEM) and X-ray diffraction (XRD) were adopted to analyze the microstructure, and morphology of the alloy. Bending and hardness test were employed to evaluate the mechanical properties of the porous TiZrNb alloy. The results show as follows:The porosity and the diameter of the pores in the alloy were decreased, and the roundness of the pores became more perfect with the pressure increasing. The longer the sintering time, the smaller the porosity and the pore diameter, and the rounder the pores were. This effect was apparent when sintering time was less than 5 hours. When the sintering temperature increased between 1000℃and 1300℃, the porosity of porous alloy decreased. The diameter of pores became bigger as the increasing of sintering temperature until it reached 1100℃, after then the diameter of pores decreased. The pores of alloy sintered at 1200℃possessed the highest roundness. The effect of NH4HCO3 on the pore characteristics was significant. The porosity of the alloy prepared with 20% NH4HCO3 was well above 40%, and the diameter of large pores of this alloy was more than 200μm. With the content of NH4HCO3 increasing, the porosity and pore diameter became larger, and the pores became rounder.The porousβ-TiZrNb alloy prepared under the condition of 20% NH4HCO3, 120MPa pressure, 1200℃sintering temperature, 5h sintering time had favorable properties with 44.04% porosity, 264.5MPa flexural strength, 17.5GPa Young's module, and 153HB Ball-pressure hardness.