Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第29卷    第11期    总第248期    2019年11月

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文章编号:1004-0609(2019)-11-2515-09
TA15钛合金等温多向锻造晶粒细化机理与力学性能
纪小虎,李 萍,时迎宾,严思梁,薛克敏

(合肥工业大学 材料科学与工程学院,合肥 230009)

摘 要: 在600 ℃条件下,对近α型TA15钛合金进行等温多向锻造实验,分别利用金相显微镜(OM)、电子背散射衍射技术(EBSD)、准静态拉伸测试和扫描电子显微镜(SEM),对其晶粒细化机理、力学性能和断口形貌进行分析。结果表明:经3道次变形后,TA15钛合金晶粒细化显著,初生等轴α相晶粒直径由9.8 μm细化至5.1 μm,次生片状α相晶粒厚度由4.6 μm降至2.3 μm;晶粒细化机理为交滑移主导的应变诱导连续动态再结晶和机械几何破碎的共同作用;材料的综合性能提升显著,极限抗拉强度升高至1782 MPa,较初始态增幅达54%,而伸长率仅下降5.8%;通过定量分析发现细晶强化和位错强化共同导致拉伸强度的提高,且晶粒细化对应的贡献更为显著。

 

关键字: TA15钛合金;等温多向锻造;晶粒细化机理;力学性能;细晶强化;位错强化

Grain refinement mechanism and mechanical properties of TA15 alloy during multi-directional isothermal forging
JI Xiao-hu, LI Ping, SHI Ying-bin, YAN Si-liang, XUE Ke-min

School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China

Abstract:The multi-directional isothermal forging (MDIF) experiments of TA15 alloy were carried out on at 600 ℃. The grain refinement mechanism, mechanical properties and fracture morphologies were analyzed by metallographic microscopy, electron backscattered diffraction, quasi-static tensile testing and scanning electron microscopy, respectively. The results show that, after 3 cycles of MDIF, the grains are refined significantly. The size of equiaxed α is reduced from 9.8 μm to 5.1 μm and the thickness of lamellar α is reduced from 4.6 μm to 2.3 μm. The grain refinement mechanism is the interaction of strain-induced continuous dynamic recrystallization by cross-slip and mechanical geometry breaking. The comprehensive mechanical properties are significantly improved. After 3 cycles of MDIF, the ultimate tensile strength increases to 1782 MPa, 54% higher than that of the initial state alloy, and the elongation rate only decreases by 5.8%. Through quantitative analysis, it is found that the combination of fine grain strengthening and dislocation strengthening results in an increase in ultimate tensile strength, and the contribution of fine grain strengthening is more significant.

 

Key words: TA15 alloy; multi-directional isothermal forging; grain refinement mechanism; mechanical properties; fine grain strengthening; dislocation strengthening

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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