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首次提出并实验证明了送粉激光熔覆过程中,熔覆材料与基材表面同时被激光加热的观点。首次提出了激光热有效利用率、透光率、吸收透光能量线密度、有效送粉系数、局部稀释率等基本概念,并给出相应参数的实验检测方法,且成功地对其进行实验检测。首次建立了:①不同条件下熔覆材料颗粒半径与工艺参数、材料物理性能之间的关系式;②透光率计算数学模型;③理论吸收透光能量线密度P_m计算模型;④显微组织分析法检测透光率估算公式;⑤基体表面单位时间内吸收热量计算模型。首次发现有效送粉系数随扫描速度增大出现极大值现象是由熔覆材料加热温度和送粉器喷嘴宽度与激光束动直径的大小决定的。当两者尺寸相当时,熔覆材料粉将得到最充分的利用。首次提出用熔覆层界面附近硬度梯度曲线及拐点连线分析研究熔履层界面附近真实稀释率。首次提出送粉激光熔覆过程中熔覆材料与熔化的基材表面撞合模型,将熔覆层分为:基体侧扩散区、撞合互混区、熔覆层侧扩散区,指出基体侧扩散区的大小、熔池结晶时原子扩散能力和程度决定熔覆层与基体界面及附近的组织结构。并在此基础上采用显微组织分析和扫描电子显微组织、成分分析、透射电子显微分析、力学性能分析等方法,研究了工艺参数对熔覆层的组织、性能及熔覆层与基体结合界?
It is first proposed and experimentally proved that the cladding material and the substrate surface are heated by laser at the same time in the powder cladding laser cladding process. For the first time, the basic concepts of the effective utilization rate of laser heat, the light transmittance, the linear density of energy absorbed and transmitted light, the effective powder feeding coefficient and the local dilution rate were put forward. The experimental testing methods of the corresponding parameters were given and the experiments were successfully conducted . For the first time established: ① under different conditions cladding material particle radius and process parameters, the relationship between the physical properties of the material; ② mathematical model of transmittance calculation; ③ theoretical absorption and transmission line energy density P_m calculation model; ④ microstructure Analytical method to measure the transmittance of the formula; ⑤ substrate surface heat absorbed per unit time model. For the first time, it is found that the maximum value of the effective powder feeding coefficient increases with the scanning speed. The maximum temperature is determined by the heating temperature of the cladding material and the width of the nozzle of the powder feeder and the diameter of the laser beam. When the two are the same size, cladding powder will be the most fully utilized. It is proposed for the first time to study the true dilution rate near the interface of the melt layer by using the hardness gradient curve near the cladding interface and the connection of inflection points. It is first proposed that the cladding material and the surface of the melted substrate collide with each other during the powder cladding laser cladding process. The cladding layer is divided into: the matrix side diffusion zone, the collision and intermix zone, the cladding side diffusion zone, The size of the diffusion zone, the atomic diffusion ability and degree of crystallization in the molten pool determine the microstructure and the interface between the cladding layer and the substrate. On this basis, the microstructure and properties of the coating and the effects of the coating and the substrate on the microstructure and mechanical properties of the coating were studied by using the methods of microstructure analysis, scanning electron microscopy, composition analysis, transmission electron microscopy and mechanical properties analysis. Combination of industry?