Thermomechanical processing(TMP)is especially crucial for metastable β titanium alloys,which has received significant attention in the community for a long time.In this contribution,the processing-responding behaviour including microstructure evolution process,texture variation mechanism,and un-derlying deformation process of powder metallurgy Ti-5553 alloy in a wide processing parameter range was comprehensively investigated.Thermal physical simulation was performed on the alloy at temper-atures ranging from 800℃ to 1100℃,and strain rates between 0.001 s-1 and 10 s-1,to varied defor-mation degrees of 20％-80％height reduction.It was found that the processing parameters(i.e.temper-ature,strain rate,and deformation degree)are influential on the deformation process and resultant mi-crostructure.Varied microstructural evolution processes for β phase including flow localization,dynamic recovery,dynamic recrystallization,and grain coarsening are activated in different processing domains,while different evolution mechanisms for a phase including dynamic precipitation,phase separation,dy-namic coarsening,and mechanical shearing also play their roles under different processing conditions.In particular,four exceptional evolution mechanisms of a'precipitation which have not been previously reported in titanium alloys were discovered and clearly demonstrated,more specifically,they are multi-interior twinning,internal compositing,layered coarsening and selective diffusion-actuated separation.After the establishment of comprehensive microstructural evolution mechanism maps,the guidance for precise processing and the knowledge reserve extension for deformation process of metastable β tita-nium alloys can be effectively achieved.

Qinyang Zhao;Leandro Bolzoni;Yongnan Chen;Yiku Xu;Rob Torrens;Fei Yang

School of Materials Science and Engineering,Chang'an University,Xi'an 710064,China;Waikato Centre for Advanced Materials and Manufacturing,School of Engineering,The University of Waikato,Hamilton 3240,New Zealand

材料科学技术（英文版）

[1]Qinyang Zhao;Leandro Bolzoni;Yongnan Chen;Yiku Xu;Rob Torrens;Fei Yang-.Processing of metastable beta titanium alloy:Comprehensive study on deformation behaviour and exceptional microstructure variation mechanisms)[J].材料科学技术（英文版）,2022(31):22-43

crostructure

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