Purpose

The purpose of this paper is to expound the relationship among microstructure, mechanical property, tribological behavior and deformation mechanism of carburized layer deposited on Ti-6Al-4V alloy by double-glow plasma hydrogen-free carburizing surface technology.

Design/methodology/approach

Morphologies and phase compositions of the carburized layer were observed by scanning electron microscope and X-ray diffraction. The micro-hardness tests were used to evaluate the surface and cross-sectional hardness of carburized layer. The reciprocating friction and wear experiments under various load conditions were implemented to investigate the tribological behavior of carburized layer. Moreover, scratch test with ramped loading pattern was carried out to illuminate the deformation mechanism of carburized layer.

Findings

Compared to substrate, the hardness of surface improved to ∼1,100 HV_0.1, while the hardness profile of carburized layer presented gradual decrease from ∼1,100 to ∼300 HV_0.1 within the distance of the total carburizing-affected region about 30 µm. The coefficient of friction, wear rate and wear morphology of carburized layer were analyzed. Scratch test indicated that the deformation process of carburized layer could be classified into three mechanisms (elastic, changing elastic–plastic and stable elastic–plastic mechanisms), and the deformation transition of the carburizing-affected region was from changing elastic–plastic to elastic mechanisms. Both the elastic and changing elastic–plastic mechanisms are conducive to the wearing course.

Originality/value

Using this technology, hydrogen embrittlement was avoided and wear resistance property of titanium alloy was greatly improved. Simultaneously, the constitutive relation during the whole loading process was deduced in terms of scratch approach, and the deformation mechanism of carburized layer was discussed from a novel viewpoint.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0489/

中文翻译：

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Ti-6Al-4V合金上无氢渗碳层的变形机理和摩擦学行为

目的

本文旨在通过双辉等离子无氢渗碳表面技术，探讨沉积在Ti-6Al-4V合金上的渗碳层的组织，力学性能，摩擦学行为和变形机理之间的关系。

设计/方法/方法

通过扫描电子显微镜和X射线衍射观察渗碳层的形貌和相组成。显微硬度测试用于评估渗碳层的表面和横截面硬度。进行了在各种载荷条件下的往复摩擦磨损实验，以研究渗碳层的摩擦学行为。此外，进行了倾斜加载模式的划痕试验，以阐明渗碳层的变形机理。

发现

与基材相比，表面的硬度提高到约1100 HV _0.1，而渗碳层的硬度分布在整个受渗碳影响的区域约30 µm的范围内 从约1100降低到约300 HV _0.1。分析了渗碳层的摩擦系数，磨损率和磨损形态。划痕试验表明，渗碳层的变形过程可分为三种机制（弹性，改变弹塑性和稳定的弹塑性机制），而渗碳影响区的变形过渡是由改变弹塑性向弹性机制转变的。 。弹性机制和不断变化的弹塑性机制都有利于穿着过程。

创意/价值

使用该技术，避免了氢脆，大大提高了钛合金的耐磨性。同时，从划痕的角度推导了整个加载过程的本构关系，并从新颖的角度探讨了渗碳层的变形机理。

同行评审

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