本文選題：超音速激光沉積　切入點(diǎn)：數(shù)值模擬　出處：《浙江工業(yè)大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：超音速激光沉積是基于冷噴涂與激光工藝的結(jié)合而發(fā)展起來(lái)的涂層工藝。通過(guò)激光對(duì)材料的加熱作用,可以提高冷噴涂層的厚度、沉積效率、致密性以及顆粒與基體的結(jié)合強(qiáng)度,并且可以實(shí)現(xiàn)難沉積材料涂層的制備,保持沉積粉末的結(jié)構(gòu)和性能。由于這些優(yōu)勢(shì)的存在,超音速激光沉積技術(shù)成為了一種可選擇的具有吸引力的技術(shù)。超音速激光沉積工藝中,能否獲得有效的沉積層,取決于沉積顆粒與基體及顆粒與顆粒間的變形行為,由于高速粒子碰撞變形瞬時(shí)性特點(diǎn),顆粒與基體變形行為不易直接觀察,所以本文利用有限元分析軟件ANSYS/LS-DYNA來(lái)模擬顆粒沉積到基體的碰撞過(guò)程。首先選取Johnson-Cook材料模型和雙線性各向同性硬化材料模型,建立超音速激光沉積三維模型,對(duì)兩種材料模型在不同入射速度、不同沉積點(diǎn)溫度下,Cu顆粒碰撞45鋼基體的沉積過(guò)程進(jìn)行了模擬分析,驗(yàn)證雙線性各向同性硬化材料模型在超音速沉積Stellite6顆粒與激光復(fù)合工藝中的可行性。選用雙線性各向同性硬化材料模型,對(duì)超音速激光沉積工藝中Stellite6顆粒與45鋼基體碰撞結(jié)合過(guò)程進(jìn)行了數(shù)值模擬分析,研究了單顆粒不同入射角度對(duì)顆粒與基體變形行為的影響,并分析研究了不同碰撞速度、不同沉積處溫度對(duì)多顆粒撞擊基體變形行為的影響。結(jié)果表明:(1)常溫下顆粒撞擊速度為800m/s和基體預(yù)熱溫度850℃、顆粒速度為500m/s時(shí),Cu顆粒與45鋼基體緊密結(jié)合形成致密涂層。Johnson-Cook材料模型和雙線性各向同性硬化材料模型仿真結(jié)果一致,兩種模型都能用于預(yù)測(cè)超音速激光沉積工藝參數(shù)。(2)顆粒的入射角度小于20°時(shí),顆粒與基體能形成緊密結(jié)合,而當(dāng)顆粒的入射角度大于20°時(shí),顆粒與基體不能形成緊密結(jié)合。(3)多顆粒碰撞基體的過(guò)程中,在鄰近顆粒間的交互作用及后續(xù)顆粒的夯實(shí)作用下,顆粒會(huì)變形,當(dāng)顆粒與顆粒間變形相匹配時(shí),顆粒間的間隙減小,形成致密結(jié)合。(4)通過(guò)激光加熱作用改善基體的力學(xué)性能和材料特性,Stellite6顆粒能沉積到45鋼基體上。
[Abstract]:Supersonic laser deposition is a coating process developed based on the combination of cold spraying and laser technology. The thickness and deposition efficiency of cold spray coating can be improved by heating the material by laser. Compactness and the bonding strength of particles to the substrate, and the preparation of coatings of refractory materials to maintain the structure and properties of deposited powders. Supersonic laser deposition technology has become an attractive alternative technology. In supersonic laser deposition process, the availability of effective deposition depends on the deformation behavior between deposition particles and matrix and between particles and particles. Because of the instantaneous characteristics of high velocity particle collision deformation, it is difficult to observe the deformation behavior of particle and matrix directly. In this paper, the finite element analysis software ANSYS/LS-DYNA is used to simulate the collision process of particles deposited into the matrix. Firstly, the Johnson-Cook material model and the bilinear isotropic hardening material model are selected to establish the three-dimensional model of supersonic laser deposition. The deposition process of two material models with different incident velocities and different deposition temperature on 45 steel matrix was simulated and analyzed. To verify the feasibility of bilinear isotropic hardening material model in supersonic deposition of Stellite6 particles and laser composite process, a bilinear isotropic hardening material model is used. In this paper, the collision process between Stellite6 particles and 45 steel matrix in supersonic laser deposition process is numerically simulated and analyzed. The effects of different incident angles of single particles on the deformation behavior of particles and matrix are studied, and the different collision velocities are analyzed. The results show that the particle impact velocity is 800 m / s and the substrate preheating temperature is 850 鈩，

本文編號(hào)：1638905