Microstructure and properties of laser shock cold rolled molybdenum strip
Molybdenum and molybdenum alloys have excellent electrical conductivity. Thermal conductivity and corrosion resistance, but also has low thermal expansion system, high hardness and high temperature strength, has been widely used. Molybdenum is a brittle material, easy to crack when forming at room temperature. Dimming impact forming is a new cold forming technology, which combines material modification strengthening and forming. Because the pulse energy and spot size of laser can be accurately controlled, the numerical control system can realize the local forming of multiple impact plate. The formability of brittle materials can be improved obviously during high speed forming, and the brittle materials can be bent or micro-formed by laser shock.
The microhardness of the impact zone is HV265-290, which is 30%-57% higher than the original hardness of l. The double effect of high strain rate cold forming and modification of the brittle material is realized. After the incomplete recrystallization at 1050 ℃/10 min/FC, the microhardness of the impact zone ranges from 220-260, which is 16%-29% higher than the original microhardness. The processed molybdenum fiber structure is maintained, and the high temperature resistance of the polycrystalline molybdenum strip is improved.
The surface microhardness of polycrystalline molybdenum strip strengthened by laser shock in the semi-lap zone conforms to the change law of Gaussian function, and the surface hardness peak changes in pattern HV265-310, which is higher than the original surface hardness HV185, and has a good impact strengthening effect.
