The microstructure and properties of Mo alloying layer after surface alloying treatment induced by continuous scanning electron beam process

Surface alloying by scanning electron beams can improve the microstructure and mechanical properties of steel. In this study. Four electron energy densities were selected during the alloying process: E1 = 1.5J/cm2, E2 = 2.9J/cm2, E3 = 4.5J/cm2 and E4 = 5.9J/cm2. The obtained results show that the sample surface is composed of alloying zone and heat-affected zone. The microstructure of the alloy zone is concealed acicular martensite and molybdenum carbide particles. The microhardness of this area is 1250HV. The sample treated with an energy density of 5.9J/cm2 has the least amount of wear. After alloying treatment, the microhardness and wear amount of the scanned samples are significantly improved.

Characterization and Tribological Behavior of Ni-Base Alloy Coatings Prepared by Electro-Spark Deposition

Ni-base alloy coatings on carbon steel surface were prepared by electro-spark deposition technology and the characterization and tribological behavior of the coatings were investigated. The research results show that the microstructure of Ni-base alloy coating can be divided into three typical areas: the white alloy zone, transition zone and overheating-affected zone. The hardness across the interface of the coating and substrate, in which chemical elements transferred from the coating to substrate, gradually decreases with the depth away from the coating surface. The friction coefficient slightly decreases, while the wear loss increases with the increase of load. The main wear mechanism of the coating is micro-cutting wear at light load friction, and gradually changes into mixture of micro-cutting wear, multi-plastic deformation wear and adhesive wear at heavy load friction.

Influence of Cr Particle Size on the Microstructure and Electrical Properties of CuW60Cr15 Composites

A series of CuW60Cr15 composites with different Cr particle size ranging from 43μm to147μm in diameter have been prepared by infiltration. The results show that the size of Cr particles plays an important role on the microstructures and the properties of the CuW60Cr15 composite. Fine Cr particle changes not only the size of the isolated CrCu alloy zone but also the structure of the skeletons of the composite obviously. Fine Cr particles increase not only the maximum and the minimum but also the mean value of breakdown voltage. Although the maximum value of chopping currents remains almost constant while Cr particles become finer, the minimum and the mean values of chopping current discernible decrease in the CuW60Cr15 composites. It can be seen from the SEM photos of the composites after arcing that the size and its location of the arc spot determines the chopping current value of the composites.

Hyperfine Fields in Ultrathin Fe and FeAu Alloy Films on Au (111)

ABSTRACTMagnetic properties of ultrathin Fe and Fe60Au40, alloy films on Au (111) were studied by SQUID Magnetometry and conversion electron Mössbauer spectroscopy. In order to get information on the influence of interdiffusion, iron films with thin alloy zones at the interfaces to Au have been prepared by co-evaporation of iron and gold and compared with iron films with presumably sharp interfaces. It was found that the presence of an 0.5 ML (Mass coverage in Monolayer) alloy zone reduces the effective magnetic interface anisotropy field and affects the growth mode of a subsequently deposited iron film such that the film is more sensitive to annealing. Groundstate Magnetic Moments and hyperfine fields are significantly enhanced in Fe/Au(111) (tFe ≤ 4 ML) and Fe60Au40 films, compared to bulk Fe.