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利用预置涂层法对三种不同成分的合金粉(Ni60A+10,15.20wt%(Ti+C))在45号钢表面进行了一系列激光表面熔覆实验。实验结果表明:利用预置涂层激光表面熔覆技术,可以在碳钢表面直接原位合成TiC颗粒增强的Ni基合金复合涂层,TiC颗粒在激光重熔过程中由石墨和钛原位反应而成。涂层与基体呈良好的冶金结合,涂层宏观质量完好,无裂纹和气孔等缺陷。涂层组织呈典型的外延生长特征,由r—奥氏体、CrB、、M_(23)C_6和TiC等相组成。原位形成的TiC颗粒与基体界面洁净,无任何附着物存在、熔覆层内TiC颗粒呈梯度分布。熔覆层内增强颗粒的数量和尺寸随涂层中添加(TiC)量的增加而增加。涂层显微硬度呈梯度分布,最大可达HV_(0.2)850,约为基材显微硬度的3.5倍。
A series of laser surface cladding experiments were carried out on the surface of 45 steel by pre-coating method on three different alloy powders (Ni60A + 10, 15.20wt% (Ti + C)). The experimental results show that TiC particles reinforced Ni-based alloy coating can be directly synthesized in situ on the surface of carbon steel by pre-coating laser surface cladding technique. The TiC particles are in situ reacted by graphite and titanium during laser remelting And into. Coating and the substrate was a good combination of metallurgical, macro-quality coatings intact, no cracks and pores and other defects. The coating has typical epitaxial growth characteristics and consists of r-austenite, CrB, M_ (23) C_6 and TiC phases. The in-situ formed TiC particles have a clean interface with the matrix without any attachments, and the TiC particles in the cladding layer have a gradient distribution. The amount and size of reinforcing particles in the cladding increases with the amount of TiC in the coating. The microhardness of the coating is gradient distribution up to HV_ (0.2) 850, about 3.5 times of the microhardness of the substrate.