【摘要】：原位力學測試技術(shù)是將材料力學性能測試與材料微觀變形損傷動態(tài)監(jiān)測相結(jié)合的一種新穎的材料測試技術(shù)，可以實時觀測材料在載荷下的微觀結(jié)構(gòu)演變和變形損傷過程，能夠為材料力學性能的測試表征以及材料及其制品的優(yōu)化設(shè)計制備提供基礎(chǔ)和支撐，對推動材料測試技術(shù)的發(fā)展具有重要意義。 本文首先綜述分析了國內(nèi)外原位測試尤其是彎曲測試技術(shù)的研究進展。原位四點彎曲測試技術(shù)在原位力學測試領(lǐng)域方興未艾，在半導(dǎo)體材料、薄膜材料、生物材料、涂層材料等的力學測試中都發(fā)揮了重要的作用。目前的原位彎曲測試多是借助國外商業(yè)化的三點/四點彎曲測試儀器，且存在價格昂貴、功能擴展性不強的缺點，而國內(nèi)對此方面的研究較少，結(jié)合此情況，本文研制了一臺能夠與超景深顯微鏡等光學顯微設(shè)備相兼容的原位四點彎曲測試裝置，裝置總體尺寸200mm105mm66mm，經(jīng)標定測試所研制裝置的載荷量程為500N、分辨率為0.1N，位移量程為10mm、分辨率為1m。論文詳細介紹了該測試裝置的結(jié)構(gòu)組成與功能原理，并結(jié)合理論計算與有限元仿真的方法對裝置的關(guān)鍵零部件進行了校核，保證測試裝置能夠正常工作。 經(jīng)過測試裝置內(nèi)的傳感器標定及初步四點彎曲試驗，所研制的原位四點彎曲測試裝置能夠滿足使用要求。針對裝置小型化后帶來的剛度不足問題，本文對原位四點彎曲裝置的機架柔度進行了分析，并利用應(yīng)變測試法測定了機架柔度系數(shù)為C=2.824610-4mm/N。而后，本文提出一種塊體材料彈性模量的四點彎曲自動測試法，并利用標定后的原位四點彎曲測試裝置測定了6061鋁合金、c11000紫銅、微晶玻璃陶瓷、K9光學玻璃四種材料彈性模量，驗證了所提方法的可行性。 有限元仿真的方法往往能夠發(fā)現(xiàn)很多試驗難以捕捉到的現(xiàn)象，在近年的力學測試領(lǐng)域發(fā)揮著越來越重要的角色。本文采用Abaqus有限元軟件模擬了6061鋁合金是四點彎曲測試過程，經(jīng)過與試驗得到的載荷-位移曲線對比，保證了仿真的合理性。主要研究了彎曲壓頭與被測試樣的接觸誤差、壓頭與試樣之間的摩擦、試樣不對稱放置等因素對四點彎曲測試結(jié)果的影響，并且研究了不同跨距比下的材料四點彎曲過程中的應(yīng)力分布規(guī)律，發(fā)現(xiàn)應(yīng)變是決定應(yīng)力分布均勻性的關(guān)鍵因素之一。 本文利用研發(fā)的測試裝置開展了7075鋁合金V型切口試樣在超景深光學顯微鏡下的原位四點彎曲試驗，在線觀察了切口附近的裂紋擴展現(xiàn)象，發(fā)現(xiàn)切口在壓應(yīng)力區(qū)域時相比在拉應(yīng)力區(qū)域材料能夠承受更大的載荷，材料的最終失效破壞多是來自于拉應(yīng)力區(qū)域的裂紋累積和擴展。另外，采用四點彎曲測試的方法對c11000紫銅和微晶玻璃陶瓷的預(yù)制壓痕變形情況進行了研究，，從微觀的角度對比了塑性材料和脆性材料的不同。
[Abstract]:In situ mechanical testing technology is a novel material testing technology which combines the mechanical properties of materials with the dynamic monitoring of microscopic deformation damage of materials. It can observe the microstructure evolution and deformation damage process of materials under load in real time. It can provide the basis and support for the testing and characterization of materials and the optimal design and preparation of materials and their products. It is of great significance to promote the development of material testing technology. In this paper, the research progress of in-situ testing, especially bending testing technology at home and abroad is reviewed and analyzed. In situ four-point bending testing technology is in the ascendant in the field of in-situ mechanical testing, and plays an important role in the mechanical testing of semiconductor materials, thin film materials, biomaterials, coating materials and so on. At present, most of the in-situ bending tests are with the help of foreign commercial three-point / four-point bending testing instruments, and have the shortcomings of high price and weak functional expansibility, but the domestic research on this field is less. Combined with this situation, a in-situ four-point bending testing device which can be compatible with optical microscopic equipment such as super-depth of field microscope is developed in this paper. The overall size of the device is 200mm 105 mm 66mm. The load range is 500N, the resolution is 0.1N, the displacement range is 10mm, and the resolution is 1m. In this paper, the structure, composition and function principle of the test device are introduced in detail, and the key parts of the device are checked with the methods of theoretical calculation and finite element simulation to ensure that the test device can work normally. Through the calibration of the sensor in the test device and the preliminary four-point bending test, the in-situ four-point bending test device can meet the requirements. In order to solve the problem of insufficient stiffness caused by miniaturization of the device, the flexibility of the frame of the in-situ four-point bending device is analyzed in this paper, and the flexibility coefficient of the frame is measured to be C 鈮

本文編號：2502405