Shanghai Optical Machinery Institute has made progress in laser assisted connection of metal carbon fiber composite heterojunction materials

Recently, the research team of Yang Shanglu from the Laser Intelligent Manufacturing Technology R&D Center of the Chinese Academy of Sciences Shanghai Institute of Optics and Fine Mechanics has made new progress in the laser assisted connection of metal carbon fiber composite heterostructure joints.

The team used an adjustable flat top rectangular semiconductor laser as a heat source to achieve the connection between high-strength steel and thermoplastic resin based carbon fiber composite materials. The relationship between the interface thermal history, interface forming mechanism, and joint performance of different materials was elucidated, and a new laser heat input process strategy was proposed.

The relevant research results are published in Composite Structures under the title of "Effect of international thermal history on bonding mechanism of laser assisted joint of QP980-FRTP with adjustable flat top rectangular laser beam".

Developing high-performance multi material hybrid structures is a development trend in the aerospace field. Carbon fiber reinforced thermoplastic composites have ultra-high specific strength and toughness, and can be mixed with metals to meet the requirements of structural lightweight and cost control. There are significant differences in physical and chemical properties between metals and composite materials, and existing methods for connecting dissimilar materials have shortcomings. It is urgent to develop high-quality and efficient new connection processes.

Figure 1. Laser assisted connection process, ultra fast laser surface treatment structure, and interface thermal history monitoring
The team studied the interface thermal history during laser assisted bonding, analyzed the temperature state of the resin matrix and its wetting behavior on the metal surface, and compared the effects of different interface thermal histories on interface bonding defects, chemical composition, joint strength, and failure behavior. By using the interface thermal history design method and laser thermal input process control, the ultimate interface temperature and sufficient insulation time have been achieved, which helps the complete melting and diffusion of the resin matrix on the metal surface, fills the micropores at the interface, promotes chemical bonding, and produces high-quality joints with peak loads above 10kN and shear strengths above 22MPa. The relevant research results have broad application prospects in aerospace and other related fields.

Figure 2. Relationship between interfacial thermal history and resin wetting behavior on metal surfaces

Source: Laser Manufacturing Network