Al含量对Ti1-xAlxN涂层组织结构、力学性能和铣削性能的影响

目的研究不同Al含量对Ti_(1-x)Al_xN涂层的影响,以获得铣削铸铁材料性能最佳的Ti AlN涂层。方法采用阴极电弧蒸发沉积法在WC-Co硬质合金表面制备两种不同Al含量的Ti_(0.5)Al_(0.5)N和Ti_(0.33)Al_(0.67)N涂层,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和电子探针微区分析仪(EPMA)分析合金的微观组织和成分组成,通过CSM纳米硬度计和纳米划痕仪测定涂层的纳米硬度、弹性模量、抗塑性变形因子、显微硬度耗散系数MDP和划痕裂纹扩展阻力CPRs等性能指标,同时比较不同Al含量涂层刀片在铣削灰口铸铁HT250和球墨铸铁QT450时的性能和磨损机理。结果 Ti_(0.5)Al_(0.5)N和Ti_(0.33)Al_(0.67)N涂层主要物相均呈NaCl型面心立方结构,以(200)方向为择优取向,且高铝涂层的XRD衍射峰向高角度偏移量大于中铝涂层,说明高铝涂层具有更高的铝固溶量。与Ti_(0.5)Al_(0.5)N涂层相比,Ti_(0.33)Al_(0.67)N涂层的抗塑性变形因子较小,MDP和CPRs较大,表现出更优的塑性、韧性和膜基结合力。在铣削HT250和QT450时,Ti_(0.33)Al_(0.67)N涂层刀片的平均寿命分别为30、60 min,相比Ti_(0.5)Al_(0.5)N涂层,切削性能更好。结论对于Ti AlN涂层来说,提高Al的质量分数至67%可以获得更优的塑性、韧性和膜基结合力,在铣削HT250和QT450时,Ti_(0.33)Al_(0.67)N涂层刀片的切削性能较优。

Effect of Aluminum Content on Microstructure, Mechanical Properties and Milling Performance of Ti1-xAlxN Coatings

The work aims to study the effect of different Al contents on Ti1-xAlxN coating so as to obtain the TiAlN coating with the best properties in milling cast iron materials. Ti0.5Al0.5N and Ti0.33Al0.67N coatings with different Al contents were de-posited on WC-Co cemented carbide substrate by cathode arc evaporation, and the microstructure and element distribution of the coatings were characterized by XRD, SEM and EPMA. The property indexes including nano-hardness (H), indentation modulus (E), factor of plastic deformation resistance (H3/E*2), microhardness dissipation parameter (MDP) and scratch crack propagation resistance (CPRs) were measured by CSM nano-hardness tester and scratch instrument. The performance and wear mechanism of coated inserts with different Al contents in milling gray cast iron HT250 and nodular cast iron QT450 were compared. Both of Ti0.5Al0.5N and Ti0.33Al0.67N coatings were NaCl face-centered cubic structure with (200) preferred orientation. XRD peak high angle offset of coatings with more Al contents was larger than that of coatings with medium Al contents, indicating that coatings with more Al contents had higher solid aluminum solution. Compared with Ti0.5Al0.5N coating, the properties H3/E*2 of Ti0.33Al0.67N coating was smaller, while MDP and CPRs were larger, which indicated better plasticity, toughness and adhesion strength. In milling HT250 AND QT450, Ti0.33Al0.67N coated inserts had average service life of 30 and 60min and better cutting performance, compared with Ti0.5Al0.5N. For TiAlN coating, the mass fraction of Al increased to 67% can obtain better plasticity, toughness and adhesion and Ti0.33Al0.67N coated inserts exhibit more excellent cutting performance in milling HT250 and QT450.