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by Ng Kwok Leung = 納米鈀硅合金之機械特性 / 吳國良. / Thesis submitted in 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Ng Kwok Leung = Na mi ba gui he jin zhi ji xie te xing / Wu Guoliang. / Acknowledgements --- p.ii / Abstract --- p.iii / 摘要 --- p.iv / Chapter Chapter 0 --- Prelude- A brief history of materials --- p.1 / Chapter Chapter 1 --- Introduction --- p.4 / Chapter 1.1 --- Introduction --- p.4 / Chapter 1.2 --- How are nanostructured materials produced? --- p.5 / Chapter 1.3 --- General properties of nanostructured materials --- p.7 / Chapter 1.4 --- Mechanical behaviour of nanostructured materials --- p.8 / Chapter 1.5 --- The solution --- p.12 / References --- p.20 / Figures --- p.22 / Chapter Chapter 2 --- Experimental --- p.30 / Chapter 2.1 --- Specimen preparation --- p.30 / Chapter 2.2 --- Means of analysis --- p.32 / Figures --- p.36 / Chapter Chapter 3 --- Synthesis of large nanostructured Pd82Si18 alloy --- p.39 / Abstract --- p.39 / References --- p.44 / Table and Figures --- p.45 / Chapter Chapter 4 --- Tensile behaviour of nanocrystalline Pd82Si18 alloy --- p.54 / Introduction --- p.54 / Experimental --- p.55 / Results --- p.57 / Discussions --- p.58 / References --- p.59 / Table and Figures --- p.60

The research work in this thesis involves an experimental and theoretical investigation for high speed machining of AISI 4140 medium carbon steels and AISI D2 tool steels which are classified as being difficult to machine materials. An experimental program was carried out to determine the cutting forces, chip formation, the secondary deformation zone thickness and surface roughness at different cutting speeds using a 0.4mm and 0.8mm nose radii ceramic tools and -7?? rake angle for annealed (virgin) AISI 4140 and heat treated AISI 4140 steel. Another series of experiments was carried out on the annealed (virgin) and heat treated AISI D2 with 0.4mm, 0.8mm and 1.2mm nose radii CBN (Cubic Boron Nitride) tools under various cutting conditions. A theoretical model is developed by taking into account the flow stress properties of the AISI 4140 (0.44% carbon content) to use with the Oxley Machining approach. To find the flow stress data for AISI D2 tool steel, the Johnson and Cook empirical constitutive equation is used as the constitutive model. In addition, the magnitude of tool radius should be also considered to determine the prediction of cutting performances. To account for the effect of nose radius edge in hard machining, a simplified geometrical method is used to model the parameters for application in the Oxley Model and works for the cutting conditions considered here. These extensions to the Oxley machining theory were verified by experimental results. These results show a good agreement between the Oxley machining theory and hard machining experiment at data. The research work described in this thesis provides useful data for hard machining conditions.

No description available.

No description available.

No description available.

The research work in this thesis involves an experimental and theoretical investigation for high speed machining of AISI 4140 medium carbon steels and AISI D2 tool steels which are classified as being difficult to machine materials. An experimental program was carried out to determine the cutting forces, chip formation, the secondary deformation zone thickness and surface roughness at different cutting speeds using a 0.4mm and 0.8mm nose radii ceramic tools and -7?? rake angle for annealed (virgin) AISI 4140 and heat treated AISI 4140 steel. Another series of experiments was carried out on the annealed (virgin) and heat treated AISI D2 with 0.4mm, 0.8mm and 1.2mm nose radii CBN (Cubic Boron Nitride) tools under various cutting conditions. A theoretical model is developed by taking into account the flow stress properties of the AISI 4140 (0.44% carbon content) to use with the Oxley Machining approach. To find the flow stress data for AISI D2 tool steel, the Johnson and Cook empirical constitutive equation is used as the constitutive model. In addition, the magnitude of tool radius should be also considered to determine the prediction of cutting performances. To account for the effect of nose radius edge in hard machining, a simplified geometrical method is used to model the parameters for application in the Oxley Model and works for the cutting conditions considered here. These extensions to the Oxley machining theory were verified by experimental results. These results show a good agreement between the Oxley machining theory and hard machining experiment at data. The research work described in this thesis provides useful data for hard machining conditions.