黏结剂喷射3D打印工业纯钛TA1的组织与性能研究

Microstructure and Properties of Commercial Pure Titanium TA1 Prepared by Binder Jet 3D Printing

目的探究不同类型黏结剂对黏结剂喷射3D打印(BJ3DP)制备TA1的C和O杂质含量、组织、性能的影响,并基于优选的黏结剂通过BJ3DP成形TA1,厘清烧结温度对微观组织、力学性能和电化学腐蚀性能的影响,为BJ3DP制备高性能TA1零件提供参考。方法基于BJ3DP打印技术,使用商用酚醛和2种自研黏结剂打印出纯钛TA1生坯,并将其固化、脱脂,随后分别在1320、1380、1440℃下烧结,对烧结后的样品进行C和O含量检测、扫描电镜测试、单向拉伸测试、电化学腐蚀试验测试。结果采用商用酚醛和SCUT-1黏结剂BJ3DP打印的TA1样品经1320℃烧结后,C和O含量较高且形成了TiC第二相,导致室温脆性较大。采用SCUT-2黏结剂BJ3DP制备TA1烧结态样品的C和O含量较低,质量分数分别为0.038%和0.100%,无第二相形成,并表现出良好的强度-塑性匹配。同时,随烧结温度的提高,基于SCUT-2黏结剂BJ3DP制备的TA1样品的相对密度从91.9%提高至95.4%,促使力学和电化学腐蚀性能同步提升。经1440℃烧结后,BJ3DP制备的纯钛TA1屈服强度为412 MPa、抗拉强度为502 MPa、断后伸长率为19.6%,在3.5%(质量分数)NaCl溶液中的腐蚀电流密度低至309 nA/cm^(2)。结论SCUT-2黏结剂适用于BJ3DP成形钛及其合金,能够获得杂质含量低且无第二相的组织,提高烧结温度可有效降低孔隙等缺陷,进而获得综合性能优异的BJ3DP零件,且其性能优于粉末注射成形(MIM)制备的TA1的性能。

The work aims to investigate the influence of different binders on the content of impurities C and O,microstruc-ture and properties of TA1 prepared by Binder Jet 3D Printing(BJ3DP),prepare TA1 samples by BJ3DP using the optimized binder to reveal the effects of sintering temperature on the microstructure,mechanical properties,and electrochemical corrosion properties,and therefore provide references for preparation of high-performance TA1 parts by BJ3DP technology.Based on Binder Jet 3D Printing,pure titanium TA1 were first printed using three different binders(phenolic resin binder and two self-developed binders),and then the printed green samples were cured and debinded.Subsequently,the samples were sintered at 1320,1380 and 1440℃.Finally,the as-sintered samples were subject to the analyses of C and O,scanning electron micro-scope,together with uniaxial tensile test and electrochemical corrosion test.The results showed that the samples fabricated by BJ3DP using phenolic resin and SCUT-1 binders after sintering at 1320℃had high contents of C and O,and had some TiC phase,thereby leading to evident brittleness at room temperature.In contrast,the samples prepared using SCUT-2 binder exhib-ited low contents of C(0.038wt.%)and O(0.100wt.%)without formation of TiC,displaying good combination of strength and ductility.In addition,as the sintering temperature increased,the relative density of the samples fabricated by BJ3DP using SCUT-2 binder increased from 91.9%to 95.4%,resulting in enhanced mechanical and electrochemical corrosion properties.The BJ3DP produced TA1 samples which were sintered at 1440℃,exhibited yield strength of 412 MPa,ultimate tensile strength of 502 MPa,the total elongation of 19.6%,and the corrosion current of 309 nA/cm^(2)in 3.5wt.%NaCl solution.It is concluded that SCUT-2 binder is suitable for BJ3DP titanium and its alloys,and texture with low impurity content and without second phase can be obtained.In the meantime,increasing sintering temperature can effectively reduce the porosity and other defects,and therefore BJ3DP TA1 parts with excellent comprehensive performance would be achieved.The BJ3DP TA1 parts would have better properties than those of their counterparts prepared by metal injection molding(MIM).