摘 要：提出通過(guò)引入外加能場(chǎng)改變焊接熱-力耦合作用，進(jìn)而控制微觀組織結(jié)構(gòu)來(lái)提高接頭質(zhì)量的新思路，開發(fā)了水冷攪拌摩擦焊方法、超聲攪拌摩擦焊方法及無(wú)輔助光源的電子束焊接圖像傳感方法，建成了水下攪拌摩擦焊接系統(tǒng)、超聲攪拌摩擦焊接系統(tǒng)和電子束焊接過(guò)程圖像傳感系統(tǒng)，為該研究的總目標(biāo)提供了硬件保障。研究了水介質(zhì)對(duì)攪拌摩擦焊接頭微觀組織和性能的作用效果，模擬分析了不同焊接環(huán)境下的溫度場(chǎng)形態(tài)及特征，研究了焊接參數(shù)對(duì)焊接溫度場(chǎng)及接頭組織和性能的影響規(guī)律，揭示了水介質(zhì)的有益作用及其本質(zhì)成因，為改善攪拌摩擦焊接頭的組織和性能奠定了理論基礎(chǔ)。針對(duì)航空構(gòu)件薄板焊接變形和焊接缺陷的問題，對(duì)比了超聲施加與否的試驗(yàn)結(jié)果，證明了超聲具有降低焊接溫度和金屬流變阻力的效應(yīng)，有利于抑制焊接缺陷和焊接變形，改善了接頭的組織和性能。研究了電子束焊接匙孔及焊縫的形成規(guī)律，分析了熔透點(diǎn)的位置特征，提出了一種基于圖像傳感進(jìn)行電子束焊接熔透點(diǎn)判別及熔深預(yù)測(cè)的方法，建立了圖像特征參數(shù)與焊接工藝參數(shù)的內(nèi)在聯(lián)系，為電子束焊接質(zhì)量的控制提供了理論和技術(shù)依據(jù)。

關(guān)鍵詞：水冷攪拌摩擦焊 超聲攪拌摩擦焊 電子束焊接 微觀組織 力學(xué)性能 作用機(jī)理

Abstract：An innovation ideal is put forward in the present project. That is to say， external energy field is introduced into welding process in order to change the thermal-mechanical coupling effect， and thus control joint microstructure and improve welding quality. Underwater friction stir welding process， ultrasonic friction stir welding process and image sensing method for observing electron beam welding process without assistant light source are developed. Correspondingly， underwater friction stir welding system， ultrasonic friction stir welding system and image sensing system for observing electron beam welding process have been established so as to provide hardware guarantee for the accomplishment of project objective. The effect of water medium on microstructures and mechanical properties of friction stir welding joints is studied， and the profile and characterization of welding temperature field are analyzed in different welding environments. The effective law of welding parameters on welding temperature field， microstructures and mechanical properties of joints is studied. The benefit effect and its essential reason of water medium are revealed so as to lay a theoretical foundation for the improvement of microstructures and mechanical properties of joints. Aiming at the welding deformation and defect of aluminum alloy sheet used in the aeronautical structure， the experimental results are compared under the conditions whether the ultrasonic wave is utilized or not. It has been demonstrated that ultrasonic wave can decrease the welding temperature and metal flowing resistance， which is benefit to restrain welding deformation and defect， and thus can improve the microstructures and mechanical properties of joints. The formation law of keyhole and weld is studied in electron welding process， and the position characterization of penetrating spot is analyzed. A method for distinguishing penetrating spot and predicting penetrating depth is put forward on the base of image sensing in the electron beam welding process， and the intrinsic relation of image characteristic parameters to welding technological parameters is established， which provides theoretical and technical basis for the control of electron beam welding quality.

Key Words：Underwater friction stir welding； Ultrasonic friction stir welding； Electron beam welding； Microstructure； Mechanical properties； Effect mechanism

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