钛粉烧结工艺参数控制研究

为得到适宜的钛粉烧结工艺参数,从而制备出全致密高性能的钛粉末冶金件,研究了烧结温度、保温时间和升温速率对烧结坯收缩率和相对密度的影响。结果表明:烧结试样的收缩率及相对密度随烧结温度、保温时间升高而增大,随升温速率减小而增大。提高烧结温度可以降低烧结坯孔隙率、减少残余孔隙尺寸,但可能导致材料力学性能下降; 保温时间达到4 h后,孔隙逐步扩散、长大和湮灭,大孔隙消失; 较低升温速率有利于组织内部缺陷消失、内应力释放和气孔消除。综合考虑烧结效率、烧结炉温度极限、烧结组织控制、烧结试样收缩率、烧结试样相对密度和节约能源等因素,选择烧结温度1200 ℃、保温时间4 h、升温速率5 ℃/min。

Experimental Study on Sintering Parameters Control of Titanium Powder

The effects of sintering temperature, holding time and heating rate on shrinkage and relative density of sintered billet were studied to get appropriate sintering  parameters for preparing fully dense titanium powder metallurgy parts with high performance. The results show that the shrinkage and relative density of the sintered sample increase with the rise of the sintering temperature and the extension of holding time, and with the decreasing of heating rate. Increasing the sintering temperature can reduce the porosity of the sintered billet and the residual void size, but it may also lead to degradation of the mechanical properties of the material. After the holding time is extended to 4 h, the voids gradually spread, grow and annihilate, and large voids disappear. A lower heating rate is beneficial to elimination of internal defects, release of internal stress and elimination of pores. With sintering efficiency, the temperature limit of sintering furnace, sintered structure control, the shrinkage rate and relative density of sample, as well as energy conservation taken into a comprehensive consideration, it is finally decided that an appropriate sintering temperature is set at 1200 ℃, holding time is 4 h, and an appropriate heating rate is set at 5 ℃/min.