Microstructures And Properties Research Of Laves Phase Strengthened Fe-Mo-Cr-Ni Wear-resistant Alloys

As a kind of strategic material, cobalt’s expensive. In China, the development ofcobalt-based high temperature wear resistant alloys which mainly consists of cobaltelement will be limited because of lacking cobalt resources. While, China has a plentyof iron resources, thus to develop a new type of iron-based high temperaturewear-resistance alloy severing in high temperature wear environments and partlyreplacing cobalt-based high temperature wear resistant alloys will bring immeasurableeconomic benefits to our country. This work was committed to the development of anew kind of iron-based high temperature wear-resistant alloy, thus microstructuresand properties of a type of recently designed Laves phase strengthened Fe-Mo-Cr-Niwear resistance alloys were studied in this work, hoping to contribute to the finaldevelopment of a practical new type of iron-based high temperature wear resistantalloy.Microstructures and properties of the newly developed Fe-Mo-Cr-Ni wearresistance alloys based on Laves phase strengthened were investigated by means ofscan electron microscope(SEM), energy disperse spectroscopy(EDS) and X-raydiffractometer(XRD), in order to study the effect of composition and heat treatmenton the microstructures and properties of it. The results indicated that as-cast alloyswhich consist of Laves phase and solid solution phase α-Fe (Mo, Cr, Ni) showcharacteristic widmanstatten microstructure and bulky dendrites. The character ofwidmanstatten microstructure disappeared after homogenization annealing, with χphase which is harmful to the alloys’ properties precipitated along the boundaries ofLaves phase as the increase of Mo and Ni content. The amount of the χ phaseincreased further after quenched.On the other hand, in order to study the mechanical properties, wear resistanceand oxidation resistance at high temperature of Fe-Mo-Cr-Ni alloys, hardness test,friction and wear experiment and anti-oxidation experiment were conducted on thealloys, then the strengthening mechanism of the alloys was analyzed. The resultsshows that, in the alloy composition on the range, the as cast alloys’ hardness range is54~59HRC and alloy composition effects less on hardness. The hardness of the alloyafter1150℃annealing treatment is lower than that of the as cast alloys. Contents ofMo and Ni had significant influence on hardness. Affecting by the amount of χ phase precipitation and the dispersion of Laves phase, alloys hardness charges in a smallrange after quenching. The wear mechanism of the as cast alloys is adhesive wear, andthe annealed alloys is abrasive wear. The wear resistance of the alloys depends on thenumber, distribution of surface oxides and sub-surface Laves phase’s strength, and itis positive correlation with the hardness of the alloys. Oxidation resistance of the alloydecreases with the increase of Mo content, while homogenization annealing treatmentcan improve the oxidation resistance of the alloys.In this experiment, FeMo25Cr14Ni10is the alloy composition with optimalorganization and the best comprehensive properties, the suggested heat treatmentprocess is homogenization annealing at a temperature above1150℃.