High-strength Lead-based Alloy And Performance

The use of nuclear energy which shows a country's comprehensive national strength is an important indicator of national economic levels and national defence, so many countyies have paid close attention to the pesceful development of nuclear energy. At present, as a result of more strict control of nuclear rediation dose, the shielding materials market become more competitive, more and more researchers having attached great importance to it. Many countries have invested a tremendous amount of manpower and material resources to conduct in-depth studies of radiation shielding materials. The developed countries, especially the United States, Japan and Russia, have formed large-scale shielding materials industries and can produce a variety of types and rang of standardized products. As a result of heavy metal lead's excellent X-ray absorption capacity, shielding materials which uses lead as basic raw material have always been widespread concerned. However, lead's low mechanical properties such as strength, shearing resistance limit its application, so the development of lead-based materials which have both ray shielding property and strength is very important.However, the current domestic and foreign high-strength lead-based shielding materials much of the development of the report. Based on long-term accumulation of research, this research group was out of the traditional technology enhanced model and prepared Pb-B-X compound nuclear shielding materials. Based on research of the lead-based shielding materials, application of a reasonable investigation and literature review, proposed adding metal Al, Ce in Pb-B-X alloys to improve mechanical properties and corrosion resistance. Pb-B-X-Al, Pb-B-X-Al-Ce alloys were prepared in order to improve mechanical properties and corrosion resistance of lead-based nuclear shielding material. At the same time to explore the relevant mechanical properties and corrosion resistance. To analyse microstructure of the samples by the use of scanning electron microscope(SEM), energy dispersive spectrometer(EDS), X-ray diffractometer(XRD). Used tensile testing, hardness testing, fracture analysis to test mechanical properties of alloys. The corrosion resistance of alloys was tested by corrosion test in solution and salt spray corrosion test, and achieved positive results, and lay the foundation for follow-up study and long-term practial application.Experimental results showed that the as cast Pb-B-X-Al microstructure with the increase of aluminum content have a significant changes. In solidifying process, the first precipitation (X-rich phase+Pb-rich phase) eutectic structue evolved from lamellar stucture into skeleton-like, lath, and finally into massive stucture. At the same time, the addition of aluminum to obtain another eutectic structure which is fine and disperse. It makes Pb-B-X-Al alloys Brinell hardness can be achieved 168N/mm2, it is about 40 times than the conventional lead alloys. The tensile strength of Pb-B-X-Al alloys reached 328MPa. At the same time also increased the corrosion resistance.The addition of Ce also have an impact on the alloys.Ce in the alloys will reacted with Al and generated needle-like Al4Ce compound, at the same time thinning the matrix stuctrue. The addition of rare earth Ce block the Pb-BX-Al alloy anode reaction process.So corrosion resistance of alloys with the Ce can be further improved, when the Ce add up to 0.8wt.%, the corrosion resistance is not increased.The results of papers descripted that considering the mechanical properties of alloys and corrosion resistance, when the aluminum its adding 15wt.%, Ce its adding 0.8wt.%, the alloys with higher strength, hardness, at the same time has some corrosion resistance and plasticity.