首页|Achieving high strength-ductility synergy in TiBw/near α-Ti composites by ultrafine grains and nanosilicides via low-temperature severe plastic deformation

Achieving high strength-ductility synergy in TiBw/near α-Ti composites by ultrafine grains and nanosilicides via low-temperature severe plastic deformation

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The common problem of low strength-ductility matching prevails in near-α high-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)6Si3 nanoprecipitates in the microstructure of TiBw/near α-Ti composites via low-temperature isothermal mul-tidirectional forging(IMDF),is expected to break the trade-off dilemma between strength and ductility.The results show that with the decrease in the temperature of IMDF,the grain scale decreased from 0.98 to 0.59 μm,and the location of silicide precipitation shifted from phase boundaries and grain boundaries to α-grain boundaries and intracrystalline regions.The experiments confirm that the local segregation of Si and the temperature of thermomechanical deformation are the key factors affecting the precipitation behavior of silicides.With the decrease of the deformation temperature,the precipitation mechanism of silicides changes from a single diffusion-controlled precipitation to the coupling of two mechanisms,namely,elemental diffusion and dislocation-assisted nucleation,which facilitates the successive precip-itation of nanometer-sized silicides at the grain boundaries and in the inner regions.The ultimate ten-sile strength(UTS)and elongation of the composites were substantially increased after IMDF at 950 and 800 ℃,especially the excellent performance at 800 ℃,where the strength reached 1320.3 MPa and the elongation was 5.8％.The room and high-temperature strengthening and failure mechanisms of the com-posites are analyzed and discussed,and the yield strength(YS)increments provided by various strength-ening mechanisms at room temperature are quantified,aiming to provide a potential preparation strategy for the synergistic strengthening of near-α TMCs with ultrafine grains and nanoparticles.

Titanium matrix compositesHigh temperature titanium alloySevere plastic deformationUltrafine grainSilicidesStrengthening mechanisms

Changjiang Zhang、Xiaojian Liang、Yonggang Sun、Shuzhi Zhang、Ruipeng Guo、Hong Feng、Fantao Kong、Peng Cao

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College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China

School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China

School of Materials Science and Engineering,Yanshan University,Qinhuangdao 66004,China

Department of Chemical and Materials Engineering,The University of Auckland,Private Bag 92019,Auckland 1142,New Zealand

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2024

10.1016/j.jmst.2024.03.047

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.202(35)