(北京有色金屬研究總院 有色金屬材料制備加工國家重點(diǎn)實(shí)驗(yàn)室，北京 100088)
摘 要: 利用分離式霍普金森壓桿(SHPB)裝置，對(duì)低間隙Ti-6Al-4V(TC4 ELI)鈦合金中4種初生α相含量不同的等軸組織在不同應(yīng)變速率(2 000、3 000和4 000 s−1)下進(jìn)行動(dòng)態(tài)壓縮試驗(yàn)，通過動(dòng)態(tài)壓縮試驗(yàn)得到材料的動(dòng)態(tài)真應(yīng)力-應(yīng)變(σ-ε)曲線，并利用金相顯微鏡(OM)等對(duì)試驗(yàn)后發(fā)生剪切失效破壞試樣的端面進(jìn)行觀察分析。結(jié)果表明：隨著初生α相含量的增加，TC4 ELI的平均動(dòng)態(tài)流變應(yīng)力、均勻動(dòng)態(tài)塑性應(yīng)變和沖擊吸收功(E)的變化規(guī)律不明顯，在4 000 s−1應(yīng)變速率加載條件下，4組試樣均發(fā)生剪切失效破壞，在失效試樣的端面觀察到幾乎呈同心的圓弧形白亮絕熱剪切帶(ASB)，部分剪切帶發(fā)生分叉，裂紋在剪切帶內(nèi)形核、長大和聚合，最終導(dǎo)致試樣斷裂。
關(guān)鍵字: TC4 ELI鈦合金；初生α相；分離式霍普金森壓桿；絕熱剪切帶
（State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:The dynamic mechanical properties of four equiaxed microstructures with different contents of primary α phase in Ti-6Al-4V extra low interstitial (TC4 ELI) were studied with split Hopkinson pressure bar device. The dynamic stress-strain curves under different conditions were obtained, and the end surfaces of samples lapsed by shear force were examined under a optical microscope. The results show that there exists no regularity on the variation of dynamic strength, dynamic strain and absorbed energy of TC4 ELI alloy with the increasing content of primary α phase. The shear failure damage occurs at the strain rate of 4 000 s−1, the white light adiabatic shear bands (ASBs) of almost concentric are-shaped are observed on the specimen face of four samples. The bifurcation of some adiabatic shear bands occurs. The cracks nucleate, grow and converge in the ASBs, eventually leading to specimen fracture.
Key words: TC4 ELI titanium alloy; primary α phase; split Hopkinson pressure bar; adiabatic shear band
