Superplastic Behavior and Deformation Mechanism of TC18 Titanium Alloy
DIAO Zhong-chi1,2, YAO Ze-kun1,2, SHEN Jing-yuan1,2, LIU Rui1,2, GUO Hong-zhen1,2
1. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China;
2. ERC of Forging Technique for Less Deformable Materials, Xi'an 710072, China
Abstract：Superplastic tensile behavior and deformation mechanism of TC18 titanium alloy were investigated by high temperature tensile test at 720-950℃ with initial strain rates of 6.7×10-5s-1-3.3×10-1s-1.The results show that under the optimal superplastic deformation condition (890℃ and 3.3×10-4s-1),the maximum elongation is 470%, the peak stress is 17.93MPa and with uniform grain size.Below the phase transus Tβ,the elongation firstly increases and then decreases.A maximum elongation of 373% is obtained at 830℃ and with initial strain rate of 3.3×10-4s-1 and the peak stress is 31.45MPa.The superplastic deformation mechanism of the TC18 titanium alloy in two-phase region is mainly grain rotation and boundary sliding,and the deformation coordination mechanism is dislocation slipping and climbing; the superplastic deformation mechanism in single phase region is intragranular dislocation motion and the deformation coordination mechanism is dynamic recovery and dynamic recrystallization.
[1] 曲凤盛,周杰,刘旭光,等.TC18钛合金热压缩本构方程及热加工图[J].稀有金属材料与工程,2014,43(1):120-124. QU F S, ZHOU J, LIU X G,et al.Constitutive equation and processing map of thermal deformation for TC18 titanium alloy [J].Rare Metal Materials and Engineering,2014,43(1):120-124.
[2] LIANG H Q,GUO H Z,NING Y Q,et al.Dynamic recrystallization behavior of Ti-5Al-5Mo-5V-1Cr-1Fe alloy[J].Materials & Design,2014,63:798-804.
[3] IMAYEV V,GAISIN R,RUDSKOY A,et al.Extraordinary superplastic properties of hot worked Ti-45Al-8Nb-0.2C alloy [J].Journal of Alloys and Compounds,2016,663:217-224.
[4] 丁凌,王志录,孙前江,等.TC6钛合金超塑性变形[J].航空材料学报,2016,36(6):23-28. DING L,WANG Z L,SUN Q J,et al.Superplastic deformation of TC6 alloy [J].Journal of Aeronautical Materials,2016,36(6):23-28.
[5] 付明杰,许慧元,刘佳佳,等.基于最大m值法和恒应变速率法的Ti3Al基合金超塑变形行为研究[J].材料工程,2015,43(11):32-38. FU M J,XU H Y,LIU J J,et al.Superplastic deformation behavior of Ti3Al based alloy based on maximum m value and constant strain rate method [J].Journal of Materials Engineering,2015,43 (11):32-38.
[6] 王晓燕,郭鸿镇,姚泽坤.双重退火对TC18钛合金等温锻件组织性能的影响[J].材料热处理学报,2009,30(1):100-103. WANG X Y,GUO H Z,YAO Z K.Effect of duplex annealing on microstructure and properties of TC18 titanium alloy isothermally forged[J].Transactions of Materials and Heat Treatment,2009,30(1):100-103.
[7] 李凯,杨平,沙爱学,等.锻态TC18钛合金棒材中β相组织和织构特征研究[J].金属学报,2014,50(6):707-714. LI K,YANG P,SHA A X,et al.Investigation of microstructure and texture of β phase in a forged TC18 titanium alloy bar[J].Acta Metallurgica Sinica,2014,50(6):707-714.
[8] 黄志涛,锁红波,杨光,等.热处理工艺对电子束熔丝成形TC18钛合金组织性能的影响[J].材料热处理学报,2015,36(12):50-54. HUANG Z T,SUO H B,YANG G,et al.Effect of heat treatment on microstructure and property of TC18 titanium alloy prepared by electron beam rapid manufacturing[J].Transactions of Materials and Heat Treatment, 2015,36(12):50-54.
[9] WANG Y,ZHANG S Q,TIAN X J,et al.High-cycle fatigue crack initiation and propagation in laser melting deposited TC18 titanium alloy[J].Minerals Metallurgy and Materials,2013,20(7):665-670.
[10] LI Z,TIAN X J,TANG H B,et al.Low cycle fatigue behavior of laser melting deposited TC18 titanium alloy[J].Transactions of Nonferrous Metals Society of China,2013,23(9):2591-2597.
[11] SHA W,MALINOV S.Titanium Alloys:Modelling of Microstructure, Properties and Applications[M].Cambridge:Woodhead Publishing,2009:265.
[12] 梁后权,郭鸿镇,宁永权,等.基于软化机制的TC18钛合金本构关系研究[J].金属学报,2014,50(7):871-878. LIANG H Q,GUO H Z,NING Y Q,et al.Analysis on the constitutive relationship of TC18 titanium alloy based on the softening mechanism[J].Acta Metallurgica Sinica,2014,50(7):871-878.
[13] JIA B H,SONG W D,TANG H P,et al.Hot deformation behavior and constitutive model of TC18 alloy during compression[J].Rare Metals,2014,33(4):383-389.
[14] 陈缇萦,聂西安,易丹青,等.TC18钛合金高温变形行为与加工图[J].热加工工艺,2012,41(21):24-28. CHEN T Y,NIE X A,YI D Q,et al.High temperature deformation behavior and processing map of TC18 titanium alloy[J].Hot Working Technology,2012,41(21):24-28.
[15] 胡静,林栋梁.金属间化合物大晶粒超塑性变形机理[J].材料热处理学报,2003,24(3):31-36. HU J,LIN D L.Superplastic deformation mechanism of large-grained intermetallic alloys[J].Transactions of Materials and Heat Treatment,2003,24(3):31-36.
[16] 胡静,林栋梁.金属间化合物大晶粒超塑性行为[J].机械工程材料,2003,27(9):1-4. HU J,LIN D L.Superplasticity of large-grained intermetallics[J].Materials for Mechanical Engineering,2003,27(9):1-4.
2017, Vol. 45 
