Studies On The Solidification Microstructure And Tribological Properties Of Highly Undercooled Ni-Pb-Cu Monotectic Alloys

In this paper, by employing the complex method of molten glass purification and superheating cycling, different undercooling Ni-20Pb-3Cu(wt.%)hypomonotectic, Ni-31.5Pb-3Cu(wt.%)monotectic, Ni-50Pb-3Cu(wt.%)hypermonotectic alloy samples were successfully prepared and the deep undercooling were obtained. The cooling curves, as well as the evolution regularity of the microstructure types, and dimension with undercooling in three Ni-Pb-Cu alloy sample were explored systematically by means of infrared radiation thermometer,XRD,SEM,EDAX etc. analytical methods. Furthermore, the tribological properties such as friction coefficient, wear loss, hardnees in dry sliding condition were systematically measured, and the effect of the microstructures on the friction and wear properties were studied; At the same time the wear and friction mechanism was discussed by the observation of wear surface by SEM and the superior alloy composition and undercooling range were commened by comparing the generalization properties of the three alloys. Finally, the technical basis of the preparation of monotectic alloys self-lubricating materials by deep undercooling method was provided. The main research work and conclusions were presented as follows:(1) The idea of preparing Ni-Pb-Cu monotectic alloy by employing the complex method of molten glass purification and superheating cycling was commended more firstly, and the technical basis of the preparation of monotectic alloys self-lubricating materials was provided by deep undercooling method.(2) The influences of undercooling on the cooling recalescence curves of three undercooled Ni-Pb-Cu alloys were systematically studied. It was found that the more undercooling degree, the larger recalescence degree, the more recalescence rate, and the shorter solidifiction time.(3) With the increase of undercooling degree of Ni-20Pb-3Cu(wt.%) hypomonotectic, Ni-31.5Pb-3Cu(wt.%) monotectic , Ni-50Pb-3Cu(wt.%) hypermonotectic alloys , The α-Ni phase in the solidicifation structure have two kinds...