块体非晶合金(La_(0.6)Ce_(0.4))_(65)Al_(10)Cu_(25)晶化行为的研究  

Crystallization Behavior of(La_(0.6)Ce_(0.4))_(65)Al_(10)Cu_(25) Bulk Metallic Glasses

作　　者：刘彤[1] 朱亚蓉[2,3] 张同文[1] 张涛[1] 

机构地区：[1]北京航空航天大学航空材料与服役教育部重点实验室,北京100191 [2]中国运载火箭技术研究院 [3]天津航天长征火箭制造有限公司,天津300462

出　　处：《稀有金属材料与工程》2012年第8期1390-1394,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50631010);国家自然科学基金面上项目(50771006);航空科学基金(2009ZF51062);高等学校博士学科点专项科研基金(20091102120009)

摘　　要：利用铜模铸造法制备(La0.6Ce0.4)65Al10Cu25块体非晶合金,通过X射线衍射和差示扫描量热法对该非晶合金的热稳定性和晶化行为进行研究。利用J-M-A方程对其等温晶化动力学进行分析,该合金平均Avrami指数在2.39～3.38之间。区域Avrami指数n(x)分析表明,晶化初期n(x)趋于3;晶化中期阶段,n(x)由2.5变化到3.5,在此过程中,当2.5<n<3时,新相长大,形核率增加,当3<n<3.5时,新相继续长大,形核率降低;晶化末期,n(x)趋于4,表明晶化过程是形核速率恒定和长大速率恒定的过程。（La 0.6 Ce 0.4） 65 Al 10 Cu 25 bulk metallic glasses（BMGs） were prepared by copper-mold casting.The crystallization behavior and thermal stability of（La 0.6 Ce 0.4） 65 Al 10 Cu 25 were investigated by X-ray diffraction and differential scanning caloricity（DSC）.The isothermal kinetics was evaluated by the Johnson-Mehl-Avrami equation.The calculated Avrami exponents were in the range of 2.39 to 3.38.The average values of local Avrami exponents show that the value of n is about 3 at the initial stage;in the middle crystallization stage,the value of n changes from 2.5 to 3.5.In this stage,for 2.5n3,the new crystallite phase grows up and the nucleation rate increases;while,for 3n3.5,the new crystallite phase continues to grow up and the nucleation rate decreases.In the final stage of crystallization,the value of n is close to 4,implying that the phase transformation occurs in a three-dimensional mode with a constant nucleation rate and a constant growth rate.

关 键 词：非晶合金 晶化行为 晶化激活能 Avrami指数 

分 类 号：TG139.8[一般工业技术—材料科学与工程]