压制压力对多孔TiAl合金孔结构及过滤性能的影响  

Effect of pressing pressure on pore structure and filtering performance in porous TiAl alloy

作　　者：张丰收[1] 贺跃辉[1] 江垚[1] 林小芹[1] 黄伯云[1] 刘咏[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2006年第4期214-218,共5页Materials Science and Engineering of Powder Metallurgy

基　　金：国家973计划资助项目(2003CB615707);国家自然科学基金项目(20476106)

摘　　要：以Ti、Al混合粉末为原料,通过反应烧结制备TiAl金属间化合物多孔过滤材料,分析压制压力对孔隙率、最大孔径及渗透系数的影响。结果表明:随着压制压力从90 MPa增加到375 MPa时,总孔隙率呈“急剧减小平缓减小平缓减小平缓减小”的变化趋势,开孔隙率呈“急剧减小平缓减小显著增大急剧减小”的变化趋势,最大孔径呈“急剧减小减小减小减小”变化,而渗透系数呈“急剧减小平缓减小平缓增大急剧减小”的变化。综合考虑压制压力对孔隙率、最大孔径及渗透系数的影响,当压制压力为250 MPa时,TiAl合金烧结坯具有较大的开孔隙率、较小的孔径和较大的渗透系数。改变颗粒之间的间隙大小及数量,从而影响反应造孔和孔隙长大,是压制压力影响孔隙率、最大孔径的机制。A porous TiAl intermetallics is fabricated using Ti and Al elemental powder by reactive sintering process, and the relationships between pressing pressure and porosity, maximum size as well as permeability coefficient are analysed. The results can be summarized as follows： under experiment condition, when pressing pressures lie in 90 MPa～375 MPa, varying trend of overall porousity is ＂rapidly decrease-gently decrease-gently decrease-gently decrease＂, varying trend of the open porousity is ＂rapidly decrease- gently decrease-increase-decrease＂, varying trend of maximum size is ＂rapidly decrease-decrease- decrease-decrease＂, and varying trend of permeability coefficient is ＂rapidly decrease-gently decrease- gently increase- rapidly decrease＂. The relationships between pressing pressure and porosity, maximum size as well as permeability coefficient are comprehensively considered, the sintered specimens of TiAl alloy has a rather large open porousity, smaller pore size and a rather large permeability coefficient when pressing pressure lies in 250 MPa. It is the acting mechanism of pressing pressure that numbers of mesopore, reactive pole and growing nucleus of aperture are changed.

关 键 词：多孔材料 TIAL合金 过滤 粉末冶金 孔结构 压制压力 

分 类 号：TF125.24[冶金工程—粉末冶金]