(南昌航空大學(xué) 航空制造工程學(xué)院，南昌 330063)
摘 要: 采用整體葉盤技術(shù)將不同性能指標(biāo)的單晶鎳渦輪葉片和多晶鎳盤片連接為一個(gè)整體，然而卻帶來盤葉連接區(qū)斷裂失效問題，嚴(yán)重制約了該技術(shù)的發(fā)展。為此，本文采用分子動力學(xué)研究單晶/多晶鎳復(fù)合體的剪切性能。首先討論了不同晶態(tài)鎳的剪切性能，然后重點(diǎn)研究了單晶/多晶鎳復(fù)合體的剪切速率效應(yīng)與溫度效應(yīng)。結(jié)果表明：相比于單晶鎳，由于多晶鎳的加入，單晶/多晶鎳復(fù)合體的整體剪切應(yīng)力水平有所下降，其剪切強(qiáng)度顯著小于單晶鎳的剪切強(qiáng)度。不同晶態(tài)鎳剪切變形進(jìn)入塑性階段后，出現(xiàn)類似于宏觀材料頸縮的現(xiàn)象，靠近頸縮區(qū)的原子發(fā)生局部錯(cuò)動、重排以及部分非晶化。隨著剪切速率的增加，單晶/多晶鎳復(fù)合體的剪切模量逐漸增大。隨著溫度升高，單晶/多晶鎳復(fù)合體剪切模量卻呈現(xiàn)下降趨勢。
關(guān)鍵字: 整體葉盤；單晶/多晶鎳復(fù)合體；分子動力學(xué)；剪切速率效應(yīng)；溫度效應(yīng)
（School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The integral blisk technology has been used to connect single crystal Ni turbine blades and polycrystal Ni discs with different performances into an integral blisk, but it has brought a high-risk failure problem in the joint area of the blisk, which seriously restricts the development of the technology. The shear mechanical properties of single crystal/polycrystalline Ni composites were studied by the molecular dynamics method. Firstly, the influence of crystalline state on the shear mechanical properties was discussed. Then, the effects of shear rate and temperature on the shear mechanical behavior of the single crystal/polycrystalline Ni composites were examined. The results show that, compared with single crystal Ni, the overall shear stress of single crystal/polycrystalline Ni composites decreases due to the addition of polycrystalline Ni. The shear strength of the single crystal/polycrystalline Ni composites is significantly smaller than that of single crystal Ni. After the shear deformation of the different crystalline Ni enters the plastic state, a phenomenon similar to that of macroscopic material necking occurs, and the atoms near the necking zone are locally dislocated, rearranged, and partially amorphized. The shear modulus of the single crystal/polycrystalline Ni composites increase with the increase of shear loading rate, while they shows a downward trend with temperature rising.
Key words: integral blisk; single crystal/polycrystalline Ni composites; molecular dynamics; shear rate effect; temperature effect
