本文關(guān)鍵詞： Al2O3陶瓷顆粒 內(nèi)生陶瓷顆粒 TiAl基復(fù)合材料 組織 壓縮性能　出處：《吉林大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：TiAl合金具有高熔點(diǎn)、低密度、高的比強(qiáng)度和比模量、低的蠕變速率和較高的抗高溫氧化能力等優(yōu)點(diǎn)，然而TiAl合金所具有的室溫本征脆性嚴(yán)重限制了其作為航空航天發(fā)動(dòng)機(jī)用高溫輕質(zhì)合金的應(yīng)用和發(fā)展。因此對(duì)TiAl合金的研究主要集中在提高強(qiáng)度和塑性上。目前，向TiAl合金基體中引入陶瓷顆粒是提高TiAl合金強(qiáng)塑性的重要方法，但是關(guān)于外加法與原位內(nèi)生這兩種陶瓷顆粒引入方式對(duì)TiAl基復(fù)合材料強(qiáng)度和塑性的影響的對(duì)比研究還較少，二者對(duì)TiAl基復(fù)合材料強(qiáng)塑性的作用機(jī)制的差別尚不明確。 因此，本論文以采用燃燒合成加熱壓一體化成型制備技術(shù)制備出的外加與原位內(nèi)生陶瓷顆粒增強(qiáng)TiAl基復(fù)合材料作為研究對(duì)象，探索外加α-Al2O3陶瓷顆粒含量、原位內(nèi)生Ti5Si3陶瓷顆粒含量、雙相內(nèi)生TiB2與Ti5Si3陶瓷顆粒比例對(duì)TiAl合金組織及壓縮性能的影響，建立組織與性能之間的關(guān)系，提出了陶瓷顆粒改善TiAl合金強(qiáng)度和塑性的機(jī)制。 本論文主要研究結(jié)果如下： 1)采用燃燒合成加熱壓的方法成功制備出外加α-Al2O3陶瓷顆粒增強(qiáng)TiAl基復(fù)合材料，及原位內(nèi)生陶瓷顆粒(Ti5Si3、TiB2、Ti5Si3-TiB2)增強(qiáng)TiAl基復(fù)合材料。發(fā)現(xiàn)外加納米α-Al2O3陶瓷顆粒團(tuán)聚體為微米尺寸，原位內(nèi)生陶瓷顆粒的尺寸則達(dá)到納米尺寸，2vol.%Al2O3/TiAl復(fù)合材料中α-Al2O3團(tuán)聚體的尺寸為1-2μm，Ti5Si3和TiB2的尺寸分別為60-90nm和30-50nm。 2)發(fā)現(xiàn)原位內(nèi)生納米TiB2與Ti5Si3陶瓷顆粒均可以細(xì)化TiAl合金的晶粒尺寸，4vol.%TiB2和4vol.%Ti5Si3陶瓷顆粒分別可以使TiAl基體的晶粒尺寸從~65μm下降到~20μm和~25μm。不同Ti5Si3含量對(duì)TiAl晶粒尺寸的影響不大。雙相(TiB2-Ti5Si3)納米陶瓷顆粒使TiAl基體晶粒細(xì)化的效果更好，，尤其當(dāng)TiB2:Ti5Si3=2:1(∑M(TiB2+Ti5Si3)=4vol.%)時(shí)，TiAl基體的平均晶粒尺寸約為15μm。 3)發(fā)現(xiàn)少量外加納米α-Al2O3陶瓷顆粒可以提高TiAl合金的強(qiáng)度，但會(huì)降低TiAl合金的塑性。2vol.%Al2O3/TiAl復(fù)合材料的屈服強(qiáng)度(497MPa)和最大抗壓強(qiáng)度(1454MPa)分別比TiAl合金高了32MPa和39MPa，壓縮斷裂應(yīng)變(14.5%)比TiAl合金低了2.8%。繼續(xù)增加α-Al2O3的含量會(huì)惡化復(fù)合材料的性能。雙相納米陶瓷顆粒具有較好的綜合力學(xué)性能，其中當(dāng)TiB2:Ti5Si3=2:1(∑M(TiB2+Ti5Si3)=4vol.%)時(shí)的綜合力學(xué)性能最佳，屈服強(qiáng)度(761MPa)、最大抗壓強(qiáng)度(1647MPa)和壓縮斷裂應(yīng)變(26.1%)分別比TiAl合金高出296MPa、232MPa和8.8%。 4)提出了外加納米α-Al2O3陶瓷顆粒及∑4vol.%不同比例原位內(nèi)生納米TiB2和Ti5Si3陶瓷顆粒對(duì)TiAl合金強(qiáng)塑性的影響機(jī)制： i)外加納米α-Al2O3陶瓷顆粒對(duì)TiAl強(qiáng)塑性的影響機(jī)制：第二相強(qiáng)化。 ii)內(nèi)生納米Ti5Si3與TiB2陶瓷顆粒提高TiAl合金強(qiáng)塑性的機(jī)制：彌散分布的第二相納米Ti5Si3與TiB2陶瓷顆粒對(duì)TiAl合金基體的強(qiáng)韌化作用和TiAl合金基體的晶粒細(xì)化。
[Abstract]:TiAl alloy has the advantages of high melting point, low density, high specific strength and modulus, low creep rate and high oxidation resistance at high temperature. However, the intrinsic brittleness of TiAl alloy at room temperature severely limits its application and development as a high-temperature light alloy for aerospace engine. Therefore, the research on TiAl alloy is mainly focused on improving strength and plasticity. The introduction of ceramic particles into the matrix of TiAl alloy is an important method to improve the strong plasticity of TiAl alloy. However, there are few comparative studies on the effect of addition method and in-situ method on the strength and plasticity of TiAl matrix composites. The difference between them on the strong plasticity of TiAl matrix composites is not clear. Therefore, the content of added 偽 -Al _ 2O _ 3 ceramic particles in TiAl matrix composites prepared by in-situ and in-situ in-situ ceramic particle reinforced composites prepared by combustion synthesis, heating and pressing, was investigated in this paper. The effect of the content of in-situ endogenous Ti5Si3 ceramic particles and the ratio of TiB2 to Ti5Si3 ceramic particles on the microstructure and compressive properties of TiAl alloy was studied. The relationship between microstructure and properties was established. The mechanism of improving the strength and plasticity of TiAl alloy by ceramic particles was put forward. The main results of this thesis are as follows:. 1) addition of 偽 -Al _ 2O _ 3 ceramic particles reinforced TiAl matrix composites and in-situ in-situ ceramic particles Ti _ 5Si _ (3) Ti _ (2) Ti _ (2) Si _ (3-TiB) _ 2) reinforced TiAl matrix composites were successfully prepared by combustion synthesis heating pressing method. It was found that the addition of 偽 -Al _ 2O _ 3 ceramic particle aggregates was of micron size. In situ, the size of in-situ ceramic particles reached the nanometer size of 2vol.Al _ 2O _ 3 / tial composites. The size of 偽 -Al _ 2O _ 3 aggregates was 1-2 渭 m Ti _ 5Si _ 3 and TiB2 was 60-90 nm and 30-50 nm, respectively. 2) it was found that in situ endogenetic TiB2 and Ti5Si3 ceramic particles can refine the grain size of TiAl alloy 4vol.and 4vol.Ti5Si3 ceramic particles, respectively, which can reduce the grain size of TiAl matrix from 65 渭 m to 20 渭 m and 25 渭 m. The effect of different Ti5Si3 content on the grain size of TiAl is discussed. TIB _ 2-Ti _ 5Si _ 3) nanocrystalline particles make the grain refinement of TiAl matrix better. The average grain size of TiAl matrix is about 15 渭 m when TiB2: Ti5Si3Si3Ti5Si3Si3Ti5Si3Ti5Si3Ti5Si3Ti5Si3Ti5Si3Ti5Si3Ti5Si3TiB2Ti5Si3Ti5Si3Ti5Si3Ti5Si3Ti5Si@@. 3) it was found that the strength of TiAl alloy could be improved by adding a small amount of nano-sized 偽 -Al _ 2O _ 3 ceramic particles. However, the yield strength and maximum compressive strength of Al _ 2O _ 3 / tial composite were decreased by 32MPa and 39MPa, respectively, and the compressive fracture strain of TiAl alloy was decreased by 2.8wt% lower than that of TiAl alloy. Further increasing the content of 偽 -Al _ 2O _ 3 would worsen the content of 偽 -Al _ 2O _ 3. Properties. Dual phase nano-ceramic particles have better comprehensive mechanical properties, The comprehensive mechanical properties of TiB2: Ti5Si3Si3Ti5Si3Si3Si3Ti4vol.are the best, the yield strength is 761 MPA, the maximum compressive strength is 1647MPA, and the compressive fracture strain is 26.1 MPA higher than that of TiAl alloy (296MPa 232MPa and 8.8MPa), respectively. 4) the mechanism of the effect of nano-Al _ 2O _ 3 ceramic particles and 鈭

本文編號(hào)：1507295