Purpose

FeNi36 (Invar-36) alloy is widely used in the fabrication of molding tools in aerospace industries but there remains a need to improve its wear and friction performance due to its relatively low hardness. The formation of a heat affected zone (HAZ) on the surface of Invar-36 cut by wire electric discharge machining (WEDM) is promising to enhance its tribological properties. This study aims to investigate the tribological performance of WEDM-treated Invar-36 via a ball-on-disk tribometer in dry-sliding conditions.

Design/methodology/approach

The untreated and WEDM-treated Invar-36 surfaces were reciprocated against an alumina ball at a sliding velocity of 40 mm/s, a stroke length of 10 mm and a sliding duration of 125 min under loads of 5, 10 and 20 N. The worn surfaces were characterized using a 2D profilometry and a scanning electron microscope equipped with energy-dispersive spectroscopy.

Findings

The results showed that the WEDM-treated surface had a superior friction coefficient and wear resistance in comparison to the untreated surface, due to the grown HAZ. There was found to be a 9.3%–11.4% decrease in the friction coefficient and a 47%–57% reduction in the wear volume after the WEDM treatment. Both the untreated and WEDM-treated Invar-36 surfaces found abrasion and plastic deformation as the dominant wear mechanisms.

Originality/value

Previous works have not focused on the tribological performance of the WEDM-treated Invar-36 extensively used for molding tools in aerospace industries. Our findings provide compelling evidence that the WEDM treatment improved the wear and friction performance of Invar-36 alloy because of the grown HAZ.

中文翻译：

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线切割FeNi36合金在不同载荷下的磨损行为研究

目的

FeNi36（Invar-36）合金广泛用于航空航天工业成型工具的制造，但由于其相对较低的硬度，仍然需要改善其磨损和摩擦性能。通过线切割放电加工 (WEDM) 在 Invar-36 表面形成热影响区 (HAZ) 有望提高其摩擦学性能。本研究旨在通过球盘摩擦仪研究干滑动条件下经线切割加工处理的 Invar-36 的摩擦学性能。

设计/方法论/途径

未处理和 WEDM 处理的 Invar-36 表面在 5、10 和 20 N 的载荷下以 40 mm/s 的滑动速度、10 mm 的行程长度和 125 分钟的滑动持续时间相对于氧化铝球进行往复运动。使用二维轮廓仪和配备能量色散光谱仪的扫描电子显微镜对磨损表面进行表征。

发现

结果表明，由于热影响区的生长，与未处理的表面相比，经电火花线切割处理的表面具有优异的摩擦系数和耐磨性。结果发现，电火花线切割处理后，摩擦系数降低了 9.3%–11.4%，磨损量减少了 47%–57%。未经处理和 WEDM 处理的 Invar-36 表面均发现磨损和塑性变形是主要的磨损机制。

原创性/价值

以前的工作并未关注广泛用于航空航天工业成型工具的经线切割加工处理的 Invar-36 的摩擦学性能。我们的研究结果提供了令人信服的证据，证明电火花线切割处理由于 HAZ 的生长而改善了 Invar-36 合金的磨损和摩擦性能。