摘要
以低成本、易变形的Ti-42Al-5Mn合金(原子分数,%)为研究对象,利用DSC、EPMA、EBSD及Pandat热力学计算软件系统研究了W含量(0.5%~1.0%)对合金相变行为和组织的影响。结果表明,随着W含量由0.5%提高至1.0%,合金β单相区开始温度(T_(β))和γ相溶解温度(T_(γ-solv))几乎未发生变化,而共析转变温度(T_(eut))稍有增加。W添加会在一定程度上影响合金固态相变路线,随着W含量增加至0.5%,合金近服役温度下的平衡相由α_(2)+γ+Laves逐渐演变为β_(o)+α_(2)+γ+Laves。W添加会对合金片层组织特征产生显著影响。在(γ+α+β)三相区处理时,随着W含量的提高,合金缓冷后组织中片层含量显著降低,当W含量为0.8%和1.0%时,合金组织以γ晶粒和βo相为主,几乎消除了α_(2)/γ层片组织。在(α+β)两相区处理时,合金缓冷后均为近片层组织,且随着W含量由0.5%提高至1.0%,片层组织晶团得到明显细化。
Advanced intermetallicβ-solidifyingγ-TiAl-based alloys have various potential applications in the aerospace and automobile industries due to their low density,functionality at higher temperatures,and high specific strength/modulus.The crucial aspect that needs to be considered when developing a newβ-solidifyingγ-TiAl alloy is to clarify the influence law ofβ-stabilizer elements on the phase transformation behavior ofγ-TiAl alloys.In this work,the impact of W contents(0.5%-1.0%,atomic fraction)on the phase transformation behavior and microstructure characteristics of Ti-42Al-5Mn-xW(atomic fraction)alloy with low cost and superior temperature workability was systematically investigated.The findings demonstrate that there were minor changes in theβ-phase single region temperature(T_(β))andγphase solvus temperature(T_(γ-solv));furthermore,the eutectoid reaction temperature(T_(eut))increases with the W content from 0.5%to 1.0%.Addition of W influences the solid phase transformation pathway to a certain extent.When the concentration of W increases to 0.5%,the equilibrium phase of the alloy at near service temperature gradually changes fromα_(2)+γ+Laves toβ_(o)+α_(2)+γ+Laves.Additionally,W addition will also have a substantial effect on the lamellar microstructure.The volume fraction of lamellar microstructure considerably decreased after alloying with(0.5%-1.0%)W for Ti-42Al-5Mn alloy when being treated in the(γ+α+β)triple-phase region followed by furnace cooling.Increasing the W content to 0.8%and 1.0%results in the development ofγandβo grain phases with almost complete removal ofα_(2)/γlamellar structures.However,the W-free and W-bearing Ti-42Al-5Mn alloys show near complete lamellar structures when treated in(α+β)two-phase region followed by furnace cooling.Furthermore,when the content of W increased from 0.5%to 1.0%,an equiaxed grain structure with refined lamellar colonies is typically obtained.
作者
李小兵
潜坤
舒磊
张孟殊
张金虎
陈波
刘奎
LI Xiaobing;QIAN Kun;SHU Lei;ZHANG Mengshu;ZHANG Jinhu;CHEN Bo;LIU Kui(Department of Materials Science and Technology Research,Ji Hua Laboratory,Foshan 528200,China;Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第10期1401-1410,共10页
Acta Metallurgica Sinica
基金
国家自然科学基金项目,No.51971215
季华实验室科研项目,No.X210291TL210。
关键词
TIAL合金
W含量
相变
片层组织
晶粒细化
TiAl alloy
W content
phase transformation
lamellar structure
grain refinement
