机械活化对Ti/Al球磨粉放电等离子烧结过程的影响  

Effect of mechanical activation on the spark plasma sintering process of milled Ti and Al powders

作　　者：张凡[1] 彭志方[1] 陈方玉[2] 阮学锋[3] 

机构地区：[1]武汉大学动力与机械学院,湖北武汉430072 [2]武汉钢铁公司,湖北武汉430080 [3]武汉大学物理学院,湖北武汉430072

出　　处：《金属热处理》2010年第9期26-30,共5页Heat Treatment of Metals

基　　金：湖北省"十五"重点攻关项目(2001AA101B02)

摘　　要：将Ti、Al单质粉在行星球磨机中以15∶1的球粉比、180 r/min的转速球磨20 h。将所得的球磨粉以100℃/min的升温速率在440~980℃以及40 MPa的压力下以放电等离子法烧结。通过XRD以及EPMA分析了烧结试样中的相及组织形貌,研究了Ti、Al球磨粉在放电等离子烧结过程中的相变规律,并将其与Ti、Al混合粉的相变规律进行对比。结果表明,Ti、Al球磨粉烧结的相变过程可分为4个阶段：颗粒软化阶段、TiAl3生成阶段、中间相生成阶段以及最终产物生成阶段。机械球磨过程细化了粉体颗粒,并发生点阵畸变,导致球磨粉的烧结过程与混合粉相比,具有反应温度低、反应快、烧结容易实现致密化的特点。由于烧结过程中没有出现液相,且高温时晶粒长大迅速,球磨粉的烧结可以由室温起施压,并需在900℃以下温度进行烧结。Elemental Ti and Al powders were milled in a planetary ball milling apparatus by 15：1 ball-to-powder rate and revolution 180 r/min for 20 h.The milled powders were sintered at a heating rate of 100 ℃/min and with a pressure of 40 MPa by spark plasma sintering（SPS）at 440-980 ℃.Phase identification and structure observation of the sintered samples were carried out by XRD and EPMA,and formation mechanism of milled Ti/Al powders during SPS was investigated and compared to that of blended Ti/Al powders.The results show that,the sintering process of milled powders can be divided into four stages： particles softening,TiAl3 formation,intermediate phase＇s formations and final product formation.Powders are fined and lattice distortion is caused by mechanical mill process.Hence the sintering process of milled powders has some advantages over blended powders of reacting at lower temperatures,completing faster and being densified easier.During the sintering process of milled Ti/Al powders,pressures can be exerted from room temperature because no liquid phase appears,and the sintering temperature can be below 900 ℃ because grains enlarge faster at above 900 ℃.

关 键 词：Ti、Al球磨粉 放电等离子烧结 扩散 机械活化 

分 类 号：TG111.6[金属学及工艺—物理冶金]