(中南大學(xué) 粉末冶金研究院，長(zhǎng)沙 410083)
摘 要: 本文采用分子動(dòng)力學(xué)模擬方法研究了Nb含量對(duì)鋯鈮合金拉伸變形行為的影響。結(jié)果表明：不同Nb含量的ZrNb合金在單軸拉伸變形中所表現(xiàn)的相變行為和純鋯相似，外加載荷會(huì)誘發(fā)合金遵循Pitsch-Schrader(PS)位向關(guān)系的密排六方結(jié)構(gòu)(HCP)到體心立方結(jié)構(gòu)(BCC)的相變，隨后BCC相沿貝恩路徑(Bain path)轉(zhuǎn)化為FCC相。通過(guò)計(jì)算不同ZrNb合金體系形成基面層錯(cuò)的能量變化，發(fā)現(xiàn)隨著Nb含量的增加，形成基面層錯(cuò)的能壘增加，即Nb的加入不利于ZrNb合金中產(chǎn)生基面層錯(cuò)。隨著Nb含量的提高，ZrNb合金的應(yīng)力-應(yīng)變曲線斜率有略微增加，彈性模量有所提高，但是合金體系的屈服強(qiáng)度逐漸降低。本研究將有助于更好地理解鋯鈮合金的變形機(jī)理。
關(guān)鍵字: 鋯鈮合金；變形機(jī)制；分子動(dòng)力學(xué)模擬
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:In this paper, the molecular dynamics simulation was used to study the influence of niobium content on the tensile deformation behavior of ZrNb alloys. The results show that the phase transformation behavior of ZrNb alloys with different Nb contents during uniaxial tensile deformation is similar to that of pure zirconium. Externally applied loading induces the hexagonal close-packed (HCP) to body-centered cubic (BCC) phase transition following the Pitsch-Schrader (PS) orientation relationship (OR). Then, the face-centered cubic (FCC) structure transforms from the BCC phase in the Bain path. By calculating the basal stacking fault energy of different ZrNb alloy systems, it is found that the energy barrier for forming basal stacking faults increases with the increasing Nb content. Therefore, it is more difficult for the generation of basal stacking faults in ZrNb alloys with a higher Nb content. With the increase of Nb content, the slope of the ZrNb alloys’ stress-strain curve increases slightly and thus the elastic modulus increases, while the yield strength of the alloy gradually decrease. This study may provide a better understanding of the deformation mechanism of zirconium-niobium alloys.
Key words: ZrNb alloy; deformation mechanism; molecular dynamics simulation
