Microstructure and properties of pure iron/copper composite cladding layers on carbon steel

In the present study, pure iron/copper composite metal cladding was deposited onto carbon steel by tungsten inert gas welding. The study focused on interfacial morphological, microstructural, and mechanical analyses of the composite cladding layers. Iron liquid–solid-phase zones were formed at copper/steel and iron interfaces because of the melting of the steel substrate and iron. Iron concentrated in the copper cladding layer was observed to exhibit belt, globule, and dendrite morphologies. The appearance of iron-rich globules indicated the occurrence of liquid phase separation（LPS） prior to solidification, and iron-rich dendrites crystallized without the occurrence of LPS. The maximum microhardness of the iron/steel interface was lower than that of the copper/steel interface because of the diffusion of elemental carbon. All samples fractured in the cladding layers. Because of a relatively lower strength of the copper layer, a short plateau region appeared when shear movement was from copper to iron.

New advances for cast iron welding in China in last decade

In this paper. the research activities in the field cast iron welding in China in China in last decade are introduced. Investigations related to hot cracking and cold cracking of cast iron welding are reviewed Development of new consumables for welding ductile iron.compacted graphite iron and austempered ductile iron are also described.

Response of structural and magnetic properties of ultra-thin FeCo–V foils to high-energy beam welding processes

Microstructural evolutions and grain-boundary-character distribution during high-energy-beam welding of ultra-thin Fe Co-V foils were studied. Detailed data about the boundaries, coincidence site lattice（CSL） relationships, grain sizes, and microstructural features were acquired from electron-backscatter diffraction（EBSD） maps. Moreover, the evolution of the magnetic properties during high-energy-beam welding was studied using vibrating sample magnetometry（VSM）. The fraction of low-angle boundaries was observed to increase in the fusion zones of both electron- and laser-beam-welded foils. The results showed that the fractions of low-Σ CSL boundaries（particularly twin boundaries, Σ3） in the fusion zones of the welded foils are higher than those in the base metal. Because the strain rates produced during high-energy-beam welding are very high（because of the extremely high cooling rate）, grain deformation by a slip mechanism is limited; therefore, deformation by grain twinning is dominant. VSM analysis showed that the magnetic properties of the welded foils, i.e., their remanence, coercive force, and energy product, changed significantly. The formation of large grains with preferred orientation parallel to the easy axis of magnetization was the main reason for the diminished magnetic properties.

Effects of Cu， Ni， Mn and Mo on the austemperability， microstructures and mechanical properties of ADI weld metal

Effect of Cu. ni. Mn and,mo on the austemperability, Inicroslruclures and Inechanlcal properlies of auslempered duclile iron(ADI) weld metal have been investigated it has been demonslrated foal Mn and.Mo obviously enhance the austemperablity of weld metal. but a exdcess of Mn or Mo impairs the mechanical properties of ADI weld metal because of the formation or carbide at cell boundaries. Cu and Ni can improve the plasticity of ADI weld metal by suppressing the formation of carbide and by increaxsing the amount of austemite,.in order to obtain the weld having both the high austemperability and exceptional combination of mechanical properties. it is advantageous that welds is alloyed withe tWo Or more elements in relalivelv.small amounts.

Non-destructive Testing Method for Crack Based on Diamond Nitrogen-vacancy Color Center

Magnetic field measurement plays an extremely important role in material science,electronic en-gineering,power system and even industrial fields.In particular,magnetic field measurement provides a safe and reliable tool for industrial non-destructive testing.The sensitivity of magnetic field measurement deter-mines the highest level of detection.The diamond nitrogen-vacancy(NV)color center is a new type of quan-tum sensor developed in recent years.The external magnetic field will cause Zeeman splitting of the ground state energy level of the diamond NV color center.Optical detection magnetic resonance(ODMR),using a mi-crowave source and a lock-in amplifier to detect the resonant frequency of the NV color center,and finally the change of the resonant frequency can accurately calculate the size of the external magnetic field and the sensi-tivity of the external magnetic field change.In the experiment,a diamond containing a high concentration of NV color centers is coupled with an optical fiber to realize the preparation of a magnetic field scanning probe.Then,the surface cracks of the magnetized iron plate weld are scanned,and the scanning results are drawn into a two-dimensional magnetic force distribution map,according to the magnetic field gradient change of the magnetic force distribution map,the position and size of the crack can be judged very accurately,which pro-vides a very effective diagnostic tool for industrial safety.