高速銑削參數對TC17鈦合金表面變質層的影響

高速銑削參數對TC17鈦合金表面變質層的影響Effect of High-Speed Milling Parameters on Surface Metamorphic Layer of TC17 Titanium Alloy

為優(yōu)化TC17鈦合金球頭銑刀高速銑削參數和為控制表面變質層提供實驗依據，采用中心復合響應曲面法，建立表面粗糙度預測模型，采用方差分析對模型和輸入參數的顯著性進行檢驗，分析銑削參數對表面粗糙度的影響規(guī)律，同時對高、中、低三種銑削參數水平下的殘余應力、顯微硬度和微觀組織進行檢測。結果表明：該模型可以有效預測球頭銑刀高速銑削TC17鈦合金后的表面粗糙度，每齒進給量和銑削寬度對表面粗糙度影響顯著；銑削后表面為殘余壓應力狀態(tài)，隨著銑削參數水平的增大，表面殘余壓應力增大，殘余壓應力層在20 μm左右；表層顯微硬度經歷了"熱軟化-加工硬化-趨于穩(wěn)定"的過程；表層晶粒出現了破碎、彎折，塑性變形層厚度約為10 μm。

In order to provide the relatively accurate experimental basis for optimizing parameters and controlling surface metamorphic layer, ball end high-speed milling experiments of TC17 titanium alloy were carried out utilizing one of experimental design techniques based on the response surface methodology. The surface roughness prediction model was built, variance analyses were applied to check the significances of surface roughness model and input parameters, the effect of parameters on surface roughness was analyzed. Meanwhile, the residual stress, microhardness and microstructure under the condition of high, medium and low level of parameters were investigated. Results indicate that the model can predict the surface roughness effectively and feed per tooth and radial depth of cut have an obvious effect on surface roughness. Compressive residual stresses are detected on all milled surfaces and surface residual stresses are increased with the increase of the level of the milling parameters. The compressive residual stress layer is approximately 20 μm regardless of milling parameters level used. The process of thermal softening, then work hardening, and finally tending to stabilize are observed in the microhardness profiles. Grains of the surface layer are broken and bent, the thickness of plastic deformation layer is approximately 10 μm.

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