磁控溅射微纳米梯度镀层对45钢及40Cr钢弹性变形性能的影响

Influence of Nano-gradient Coatings on the Elastic Deformation Properties of 45 Steel and 40Cr Steel Deposited by Magnetron Sputtering

利用磁控溅射离子镀技术在屈强比不同的45钢及40Cr钢基体上制备Cr、类石墨碳(Graphite-like-carbon,GLC)及CrTiAlN微纳米梯度镀层,通过考察镀层/金属复合体系弹性模量和屈服强度的变化来研究镀层对基体弹性变形行为的影响。研究结果表明:磁控溅射离子镀层可以改善金属基体的弹性变形性能,但镀层对不同金属基体力学参量的影响不同;屈强比低的45钢,镀层可同时提高弹性模量和屈服强度,在v=0.1mm/min的低速拉伸时,45钢试样的屈服强度可提高20%左右;屈强比高的40Cr钢,镀层对其屈服强度基本无影响,但对弹性模量提高的程度更显著,当拉伸速度为0.7mm/min时,40Cr钢试样的弹性模量可提高60%,而45钢仅为22%;镀层/基体复合体系的弹性模量随拉伸速度的增加表现为先增大后减小的特点,其变化规律不同于金属基体;镀层的高硬度和良好的膜基匹配能力有助于阻碍工件表面及亚表面微塑性形变区的扩展,从而提高试样的力学性能。

Cr,GLC（graphite-like-carbon） and CrTiAlN nanoscaled coatings are deposited by using magnetron sputtering on 45 steel and 40Cr steel of different yield-strength ratios.The influence of the coatings on the ability of elastic deformation of metal matrix is investigated by measuring the changes of elastic modulus and yield stress.The results show that all coatings can improve elastic deformation properties of metal substrate,but the effect on different steel is different.For 45 steel which has lower yield-strength ratio substrate,elastic modulus and yield stress can be enhanced by coatings.When the v =0.1 mm/min,the yield stress of it can be increased 20%.As to 40Cr steel,the coatings can raise elastic modulus markedly but have no effect on yield stress.When the v =0.7 mm/min,the elastic modulus can be increased by 60% on 40Cr sample but only by 22% on 45 steel sample.Different from metal material＇s,the elastic modulus of the coating/substrate complex ascends the top then descends gradually with the increase of tensile speed.The prominent hardness and excellent adhesion of coating can inhibit expansion of the deformation area,thereby improving the mechanical properties of the sample.