Development of a mini-tribometer for in-situ observation of subsurface and the corresponding experiments

Abstract

Purpose This paper aims to develop a Mini-Tribometer for in-situ observation of subsurface. Design/methodology/approach To observe the change of the microstructure during wear in real time, an in-situ observation mini-tribometer was developed according to the requirements of the basic frictional experiments and carried out the verification experiments. Findings The subsurface images and the tribological data obtained from the mini-tribometer clearly show that the graphite in the matrix moves to the surface and takes part in lubrication mainly in the form of extrusion and peeling off, and the migration of graphite in the copper-based composite to the frictional interface to act as lubricant and to result in the decrease of the friction coefficient. The experimental results of the developed tribometer are accurate, which can provide important references for further research on the wear mechanism of materials. Originality/value The developed in-situ observation mini-tribometer can be used to observe the dynamic wear mechanism of the frictional pairs, which is very important for optimization of material design and tribological performances.

Using DEM method to study graphite migration of copper-based graphite composites during friction

“…In the tests, copper-based graphite composite with the graphite content of 6vol%, 8vol%, 10vol%, 12vol%, 14vol%, the graphite size of 2 μm, 15 μm, 30 μm, 45 μm, 60 μm were selected as the experimental research object, respectively, and the powder metallurgical method was employed to prepared the composite, the composite size was 5 × 5 × 20 mm. A self-made in-situ observation friction tester was used in the test 27 The friction pair was 45 steel with a diameter of 30mm, and the friction condition was dry friction, the contact mode was ring-block, the relative sliding speeds were 0.1m/s, 0.15m/s, 0.2m/s, 0.25m/s, 0.3m/s, and applied loads were 6N, 8N, 10N, 12N, 14N, respectively. The friction test lasted for 20 min.…”

Effect of the near-surface pore volume evolution on graphite migration of copper-based graphite composite during friction

“…testing equipment was a in-situ observation tribometer. 30 The 45 steel with a diameter of 30 mm was used as friction pair, and the test condition was dry friction, the contact mode was ring block, the friction pair relative sliding speed was 0.2 m/s and the load was 12N, the friction test lasted for 20 min, (time step 10000000 was a stable wear stage. In our test, when the test time was 20 min, it was also a stable wear stage).…”

“…Actually, it is difficult to monitor the single graphite particle movement in the composite, but it is possible to judge the whole graphite movement, so as to determine the overall graphite migration speed. In our work, based on the HSI color separation selection method, the surface pore structure of the sample was binarized, and the variation of the sample surface pores graphite was calculated by image-Pro Plus software before and after the friction test, which was used to determine the graphite migration speed, 30 Figure 9 shows graphite area calculation steps. In order to better study the graphite migration speed, it can be expressed by the following equation: …”