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烧结温度对多孔Ti600合金孔隙结构及力学性能的影响

Effect of sintering temperature on pore characteristics and mechanical properties of porousTi600 alloys

  • 摘要: 以Ti600高温钛合金粉末(Ti–6.0Al–2.8Sn–4.0Zr–0.5Mo–0.4Si–0.1Y)为基体,尿素为占位体,采用粉末冶金法制备多孔钛材料,利用光学金相显微镜、扫描电镜以及万能力学试验机系统探究烧结温度对多孔钛结构特征及力学性能的影响。结果表明:随着烧结温度升高,多孔钛的孔壁逐渐致密化,孔隙率、孔径尺寸均呈降低趋势,孔隙率由67.61%降低至61.31%,孔径由1.233 mm降低至1.194 mm。压缩强度随温度提升持续增加,在1300 ℃达峰值82.08 MPa,1400 ℃时降至78.20 MPa;杨氏模量在1300 ℃达最优值1.735 GPa,1400 ℃时因晶粒粗化降至1.719 GPa;能量吸收效率于1300 ℃达到最高值28.131 MJ/m3。综合结构特征与性能指标,1300 ℃为最佳烧结温度,此时孔壁充分致密且孔隙分布均匀,同时兼具最高压缩强度与最优能量吸收能力。

     

    Abstract: Using Ti600 high-temperature titanium alloy powders (Ti–6.0Al–2.8Sn–4.0Zr–0.5Mo–0.4Si–0.1Y) as the matrix and urea as the space holder, the porous titanium materials were fabricated via powder metallurgy. The effects of sintering temperature on the structural characteristics and mechanical properties of porous titanium materials were systematically investigated by optical metallographic microscope, scanning electron microscope (SEM), and universal mechanical testing machine. The results show that with the increase of sintering temperature, the pore walls of porous titanium gradually densify, and both the porosity and pore size exhibit the decreasing trend, the porosity decreases from 67.61% to 61.31%, and the average pore size reduces from 1.233 mm to 1.194 mm. The compressive strength rises continuously with temperature, reaching a peak of 82.08 MPa at 1300 ℃, then dropping to 78.20 MPa at 1400 ℃. The Young’s modulus reaches the optimal value of 1.735 GPa at 1300 ℃, and decreases to 1.719 GPa at 1400 ℃ due to grain coarsening. The energy absorption efficiency peaks at 28.131 MJ/m3 at 1300 ℃. Comprehensively considering the structural characteristics and performance, the optimal sintering temperature is determined as 1300 ℃. The pore walls are fully densified with the uniform pore distribution at 1300 ℃, and the porous titanium simultaneously achieves the highest compressive strength and optimal energy absorption capacity.

     

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