Sahasrabudhe Himanshu, Soderlind Julie, Bandyopadhyay Amit
W. M. Keck Biomedical Materials Research Laboratory School of Mechanical and Materials Engineering Washington State University Pullman, WA 99164-2920, USA.
W. M. Keck Biomedical Materials Research Laboratory School of Mechanical and Materials Engineering Washington State University Pullman, WA 99164-2920, USA.
J Mech Behav Biomed Mater. 2016 Jan;53:239-249. doi: 10.1016/j.jmbbm.2015.08.013. Epub 2015 Aug 17.
Laser remelting of commercially pure titanium (CP-Ti) surface was done in a nitrogen rich inert atmosphere to form in situ TiN/Ti composite coating. Laser surface remelting was performed at two different laser powers of 425 W and 475 W. At each power, samples were fabricated with one or two laser scans. The resultant material was a nitride rich in situ coating that was created on the surface. The cross sections revealed a graded microstructure. There was presence of nitride rich dendrites dispersed in α-Ti matrix at the uppermost region. The structure gradually changed with lesser dendrites and more heat affected α-Ti phase maintaining a smooth interface. With increasing laser power, the dendrites appeared to be larger in size. Samples with two laser scans showed discontinuous dendrites and more α-Ti phase as compared to the samples with one laser scan. The resultant composite of TiN along with Ti2N in α-Ti showed substantially higher hardness and wear resistance than the untreated CP-Ti substrate. Coefficient of friction was also found to reduce due to surface nitridation. Leaching of Ti(4+) ions during wear test in DI water medium was found to reduce due to laser surface nitriding.
在富氮惰性气氛中对工业纯钛（CP-Ti）表面进行激光重熔，以形成原位TiN/Ti复合涂层。在425 W和475 W两种不同的激光功率下进行激光表面重熔。在每种功率下，通过一次或两次激光扫描制备样品。所得材料是在表面形成的富含氮化物的原位涂层。横截面显示出梯度微观结构。在最上部区域存在分散在α-Ti基体中的富含氮化物的树枝晶。结构逐渐变化，树枝晶减少，热影响的α-Ti相增多，保持界面光滑。随着激光功率的增加，树枝晶尺寸似乎更大。与单次激光扫描的样品相比，两次激光扫描的样品显示出不连续的树枝晶和更多的α-Ti相。α-Ti中TiN与Ti2N的所得复合材料显示出比未处理的CP-Ti基体更高的硬度和耐磨性。由于表面氮化，摩擦系数也降低。发现在去离子水介质中进行磨损试验期间，由于激光表面氮化，Ti(4+)离子的浸出减少。
