Pulse laser surface melting method for achieving grain shape regulation of titanium alloy surface

Abstract

The invention discloses a pulse laser surface melting method for achieving grain shape regulation of a titanium alloy surface. The method includes first preliminarily optimizing a laser surface melting process window and recording the fixed-point temperature change of the molten pool surface during the laser melting process under the optimized process window to obtain a fixed-point thermal cycle curve and the average cooling rate Xi at the molten pool center; When Xi<=2*10<3>DEG C / s and Xi / V2>=5*10<8>DEG Cs / m<2>, providing continuous laser for columnar crystal with the laser power of 400-900Wand the scanning speed of 6-10mm / s; when 2*10<3><= Xi <=10<5>DEG C / s and Xi / V2<=10<6>DEG Cs / m<2>, providing pulse laser with square waveform for isometric crystal with the laser power of 600-1000W andthe scanning speed of 4-8mm / s; finally obtaining the titanium alloy surface with the beta crystal form regulated. By means of the method, regulation of the beta crystal shape on the titanium alloy surface is achieved, and the mechanical property of a formed part can be effectively improved.

Description

technical field [0001] The invention relates to the field of laser metal material processing, in particular to a pulsed laser surface melting method for realizing regulation and control of titanium alloy surface crystal grains. Background technique [0002] Titanium alloys are widely used in aerospace, chemical industry, energy and biomedical fields due to their high specific strength, good biocompatibility and corrosion resistance. However, titanium alloys have problems such as low surface hardness, poor wear resistance, easy adhesive wear with contact materials, and poor corrosion resistance in reducing acids. These problems limit the wider industrial application of titanium alloys. Surface treatment (such as nitriding, carbonitriding, physical vapor deposition, chemical vapor deposition, and laser surface treatment, etc.) can be used as an effective method to improve the surface properties of titanium alloys. Among them, the laser beam has strong convergence, high energy ...

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Problems solved by technology

The above research provides a good insight and theoretical basis for the regulation of the β-crystal morphology of laser surface fused titanium alloys. However, there is still a lack of effective methods to effectively control the β-crystal morphology of laser surface-modified titanium alloys.

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