Achieving superior mechanical properties in friction lap joints of copper to carbon-fiber-reinforced plastic by tool offsetting. Issue 9 (September 2018)

• Record Type: Journal Article
• Authors: Wu, L.H.; Nagatsuka, K.; Nakata, K.
• Is Part Of: Journal of materials science & technology. Volume 34:Issue 9(2018)
• Page Start: 1628
• Page End: 1637
• Publication Date: 2018-09
• Subjects: Hybrid joining -- Plastic -- Metal -- Carbon-fiber-reinforced plastic -- Properties; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2018.04.015
• Languages: English
• ISSNs: 1005-0302

Abstract

Graphical abstract: Highlights: Carbon-fiber-reinforced thermoplastic was directly joined to Cu by normal friction lap joining (FLJ) and FLJ with tool offsetting. Tool offsetting decreased the non-uniform temperature distribution, thereby enhancing the joint strength from 0.89–2.25 kn into 1.71–3.54 kn. Tool offsetting increased the joint strength by 135%, with the bubble area only 19% of the original level. The large increase of joint strength was attributed to increased joining area, reduced bubbles and reduced degradation of plastic. Tool offsetting was a good way to obtain a high strength joint with very few bubbles. Abstract: It is a challenge to achieve a sound welded metal/carbon-fiber-reinforced thermoplastic (CFRTP) joint with high strength and few bubbles. In this study, sound lap joints of Cu and CFRTP were obtained by friction lap joining (FLJ) directly at rotation rates of 600–2000 rpm, with the welding tool at the joint center and offsetting the tool 7 mm away from the center toward the retreating side, respectively. Tool offsetting reduced the non-uniform temperature distribution in the lap joints resulting from the high conductivity of Cu, which not only enhanced the tensile shear force from 0.89–2.25 kN to 1.71–3.54 kN, with the maximum increasing rate of 135%, but also reduced the bubble area to only 19% of the original level of 2000 rpm. It is the first time to report a high-quality Cu/CFRTP joint with a high strength and few bubbles. The large increase of the strength after tool offsetting was attributed to the increase of the joining area, the decrease of bubbles and the decrease of the CFRTP degradation. The details on the generation, quantitative distribution and expulsion of the bubbles in the FLJ joints were discussed.