本文選題：鈦合金　切入點：電脈沖熱處理　出處：《北京理工大學》2015年碩士論文

【摘要】：鈦合金具有密度小、比強度、抗腐蝕性能好等諸多優(yōu)異性能，是較為理想的輕質裝甲金屬材料。有研究表明，在防護性能相同的情況下，鈦合金裝甲的重量比裝甲鋼輕25%。然而，鈦合金是一種高絕熱剪切敏感性的材料，在高速變形過程中極易以絕熱剪切的形式失效，嚴重限制了它在裝甲防護領域的應用。針對以上問題，本文以熱軋Ti-6Al-4V合金（簡稱為TC4合金）為研究對象，以降低其絕熱剪切敏感性為研究目標，采用特殊電脈沖熱處理的方法，對熱軋TC4合金的微觀組織細節(jié)特征進行調控，系統(tǒng)地研究了電脈沖熱處理對熱軋雙態(tài)TC4合金和熱軋等軸TC4合金微觀組織和力學性能的影響規(guī)律及機理。得出如下主要結論： 電脈沖熱處理可以使熱軋TC4合金的組織在數(shù)分鐘內轉變成魏氏組織，且熱處理溫度越高，轉變成魏氏組織所需要的保溫時間越短；組織轉變成魏氏特征之前，原始熱軋組織僅發(fā)生再結晶；轉變成魏氏組織之后，β晶粒和片層寬度隨著熱處理溫度的上升和保溫時間的延長而增大。 熱軋雙態(tài)組織TC4合金經電脈沖熱處理后，，僅發(fā)生再結晶而未發(fā)生魏氏轉變的組織其準靜態(tài)壓縮塑性顯著提高，且破壞強度也隨之提高；而一旦組織轉變成魏氏組織，其臨界失效應變顯著降低，最終的破壞強度也呈現(xiàn)降低的趨勢。熱軋等軸組織TC4合金經電脈沖熱處理后，準靜態(tài)壓縮塑性顯著提高，但強度略有降低；剛剛完成組織轉變、具有較細晶粒的魏氏組織合金具有最大的準靜態(tài)臨界失效應變。電脈沖熱處理可以顯著提高熱軋TC4合金的動態(tài)臨界破壞應變值和發(fā)生剪切破壞前的單位體積吸收功，即可以顯著提高材料的抗絕熱剪切破壞能力，但對動態(tài)強度未產生明顯影響。熱軋雙態(tài)組織TC4合金經800℃/20min電脈沖處理后臨界剪切破壞應變值比原始熱軋鈦合金提高了76.6%，絕熱剪切破壞前的材料單位體積吸收功提高了75.8%。熱軋等軸組織TC4合金經1000℃/5min電脈沖處理后臨界剪切破壞應變值相比原始熱軋TC4合金提高了133%，單位體積吸收功提高了192%。 在動態(tài)加載條件下，絕熱剪切帶在電脈沖熱處理后轉變成的魏氏組織中擴展時出現(xiàn)分叉現(xiàn)象，擴展路徑變得更加曲折；且在主剪切帶周圍組織中發(fā)現(xiàn)均勻變形區(qū)，消耗了大量的沖擊功，推遲了裂紋的萌生和擴展，因此電脈沖熱處理后發(fā)生魏氏組織轉變的合金動態(tài)塑性顯著增強，絕熱剪切敏感性顯著降低。
[Abstract]:Titanium alloy has small density, specific strength, good corrosion resistance and other excellent properties, is an ideal light armored metal materials. Studies have shown that the protection performance under the same weight of titanium alloy armor than light armor steel 25%. however, titanium alloy is a kind of high adiabatic shear sensitivity of materials. Easy to form adiabatic shear failure in the deformation process of high speed, seriously limit its application in armor protection field. To solve the above problems, based on the hot rolled Ti-6Al-4V alloy (TC4 alloy) as the research object, in order to reduce the adiabatic shear sensitivity as the research object, using the method of special electric pulse heat treatment, microstructure detailed microstructure characteristics of the hot rolled TC4 alloy to control, systematically studied the electric pulse heat treatment on the microstructure and mechanical hot rolled dual phase TC4 alloy hot rolling shaft and properties of TC4 alloy and the influence law of the mechanism. The main conclusions are as follows:
Electric pulse heat treatment can improve the microstructure of the TC4 alloy hot rolled into widmanstatten structure in a few minutes, and the higher the temperature, into the widmanstatten structure required shorter holding time; before the organization into widmanstatten characteristics, original microstructure occurs only after recrystallization; into widmanstatten structure, grain and film layer width increases with the increase of heat treatment temperature and holding time.
Hot rolled duplex microstructure of TC4 alloy by electric pulse after heat treatment, only the recrystallization and not change the Widmanstaten quasi-static compressive plasticity increased significantly, and the failure strength was increased; and once the organization turned into widmanstatten structure, the critical failure strain decreased significantly, the ultimate failure strength also decreased hot rolled equiaxed microstructure of TC4 alloy by electric pulse after heat treatment, the quasi-static compression plastic significantly improved, but the strength decreased slightly; just completed the transformation, has a fine grain widmanstatten alloy has the largest quasi static critical failure strain. The electric pulse heat treatment can significantly improve the dynamic critical failure strain of hot rolled TC4 alloy and the shear failure occurred before the unit volume of absorbing received power, which can obviously improve the anti adiabatic shear damage ability, but did not have a significant effect on the dynamic strength of hot rolled dual state. The microstructure of TC4 alloy by 800 DEG /20min after electric pulse treatment of critical shear strain value than the original hot rolled titanium alloy is increased by 76.6%, the adiabatic shear failure before the unit volume of material absorption power is increased by 75.8%. hot equiaxed microstructure of TC4 alloy by 1000 DEG /5min after electric pulse treatment of critical shear strain values compared to the original hot rolling TC4 alloy increased 133%, the unit volume power absorption increased by 192%.
Under dynamic loading, the adiabatic shear band bifurcation phenomena in electric pulse expansion after heat treatment into the widmanstatten structure when the propagation path becomes more tortuous; and in the main shear zone found uniform deformation zone in the surrounding tissue, consumes a large amount of impact energy, delayed the initiation and propagation of crack, dynamic alloy so the electric pulse heat treatment after widmanstatten microstructure plastic significantly enhanced adiabatic shear sensitivity significantly reduced.

【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG337.6

【參考文獻】

相關期刊論文 前10條

1 孫智;蘇鐵健;李淑華;王富恥;;高應變率下工業(yè)純鈦TA2變形與失效研究[J];兵器材料科學與工程;2007年03期

2 張旺峰;黃旭;李興無;馬濟民;曹春曉;;鈦合金的設計方法及其研究進展[J];材料導報;2005年03期

3 洪權,趙永慶,楊冠軍,曾衛(wèi)東;Ti-6Al-4V合金包覆疊軋薄板的加工工藝與組織性能研究[J];材料工程;2004年11期

4 馮海波,周玉,賈德昌;放電等離子燒結技術的原理及應用[J];材料科學與工藝;2003年03期

5 沈以赴,郭曉楠,張坤,李順林,周本濂;脈沖電流對金屬材料的作用及其研究進展[J];材料科學與工程;1998年03期

6 李建崇;李樹奎;范群波;裴傳虎;;鍛造工藝對Ti-6Al-4V-4Zr-Mo合金絕熱剪切敏感性的影響[J];稀有金屬材料與工程;2010年S1期

7 郭強;王清;韓秀麗;魯學錕;孫東立;武高輝;;大變形Ti-15-3合金時效過程中α相的析出行為及力學性能(英文)[J];稀有金屬材料與工程;2011年03期

8 劉睿;惠松驍;葉文君;熊柏青;尤振平;;退火溫度對TC4鈦合金動態(tài)斷裂韌性的影響[J];稀有金屬材料與工程;2011年10期

9 ;鈦及鈦合金在裝甲車輛上的應用[J];稀有金屬材料與工程;1994年02期

10 劉志義,鄧小鐵,王引真;脈沖電流對2091鋁鋰合金動態(tài)再結晶動力學的影響[J];材料研究學報;2001年03期

本文編號：1709880