The real contact area (RCA) of randomly rough contacts has received a great deal of attention because it correlates strongly with friction, lubrication, sealing, and conductivity. Simulations have revealed that the RCA associated with deterministic normal squeezing loads increases when tangential loads are also applied, in a phenomenon called junction growth. However, experimental investigations of the junction growth of randomly rough contacts are rare. Here, we used X-ray computed tomography (CT) to measure junction growth when two aluminum alloy surfaces were in contact. A high-resolution experimental setup was used to apply loads and observe contact behaviors at a resolution of 4 µm. The RCA and average contact gaps were computed using a three-dimensional (3D) geometric model constructed from gray CT images using the Otsu thresholding method. The results showed that the RCA increased as the normal load increased. The RCA increased by 22.67% after a tangential load was applied (junction growth), and the average gap decreased by 14.01% after a tangential load was applied. Thus, X-ray CT accurately measured the junction growth as a novel quantitative method.

随机粗糙接触的真实接触面积（RCA）受到了极大的关注，因为它与摩擦、润滑、密封和导电性密切相关。模拟表明，当还施加切向载荷时，与确定性正常挤压载荷相关的 RCA 会增加，这种现象称为结增长。然而，对随机粗糙接触的结生长的实验研究很少。在这里，我们使用 X 射线计算机断层扫描 (CT) 来测量两个铝合金表面接触时的结生长。使用高分辨率实验装置以 4 µm 的分辨率施加载荷并观察接触行为。 RCA 和平均接触间隙是使用 Otsu 阈值方法根据灰度 CT 图像构建的三维 (3D) 几何模型来计算的。结果表明RCA随着正常负荷的增加而增加。施加切向载荷后，RCA 增加了 22.67%（结增长），施加切向载荷后，平均间隙减小了 14.01%。因此，X 射线 CT 作为一种新颖的定量方法准确测量了结的生长。