Ti6Al4V钛合金表面Zr-N合金化层的抗高温摩擦磨损性能  

Tribology Behavior of Zr-N Alloying Layer on Ti6Al4V Alloy Surface at Elevated Temperature

作　　者：汤金钢[1] 刘道新[1] 唐长斌[1] 于首明[1] 张晓化[1] 

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2013年第2期331-335,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金资助(51171154;51101127)

摘　　要：为了改善钛合金的高温耐磨性能,采用锆-氮离子共渗与异步渗(渗锆后再氮化处理)两种工艺技术分别在Ti6Al4V钛合金表面制备致密的锆-氮合金化改性层,对比研究了合金化层的组织结构特征和高温摩擦磨损性能。结果表明,两种工艺制备的Zr-N合金层表面均由ZrN相组成,异步渗改性层的内层则包含较厚的Zr-Ti固溶体,两种等离子表面合金化层均使钛合金表面硬度显著提高。同样温度和处理时间条件下,异步渗合金化层的厚度约为锆-氮共渗合金化层厚度的6倍,且氮化物层也较厚,原因归于前者处理过程中Zr与Ti之间良好固溶特性的充分发挥及ZrN相的扩散障作用的有效抑制。300℃高温下球盘摩擦磨损试验结果表明,由于锆-氮共渗合金化层深度较小,因而改善钛合金基材耐磨性能的效果相对较低。锆-氮异步渗处理则使Ti6Al4V钛合金耐磨性能显著提高,摩擦因数降低50%以上,比磨损率降低2个数量级,原因归于该类合金化层高的表面硬度、大的层深、良好的高温抗氧化性能及优异表面承载能力的有机匹配。The dense Zr-N alloying layers were prepared on the surface of Ti6Al4V alloy by two kinds of surface alloying processes to improve the wear resistance of Ti alloy at elevated temperature. One process is Zr-diffusing with nitriding simultaneously （synchronous surface alloying）, and the other is nitriding after Zr-diffusing （asynchronous surface alloying）. The microstructure and tribological property at elevated temperature of the modified surface layers were investigated. Results show that both the Zr-N diffusion layers consist of ZrN phase, and the asynchronous surface alloying with thick Zr-Ti solid solution layer is beneath the surface. The surface microhardness of the Ti6Al4V alloy was significantly increased by both Zr-N alloying layers. With the same time and temperature, the thickness of the asynchronous surface alloying layer was about 6 times of the synchronous surface alloying layer, because the asynchronous surface alloying has excellent solution and low diffusion inhibition. The results of the ball-on-disc wear tests indicate that the wear resistance at 300 °C of the synchronous surface alloying layer was not significantly improved because of the shallow diffusion depth. The asynchronous surface alloying reduced the wear rate obviously by two orders and the friction coefficient by 50% due to the high surface hardness, thick depth, good thermal oxidization resistance and big surface load-bearing ability.

关 键 词：钛合金 离子渗锆 离子氮化 高温磨损 

分 类 号：TG174.44[金属学及工艺—金属表面处理]