Based on an assumption that the effective pressure in hot pressing related to the applied pressure varies with the relative density of the compact in a power law form. a three-dimensional viscoelastic model that depic...Based on an assumption that the effective pressure in hot pressing related to the applied pressure varies with the relative density of the compact in a power law form. a three-dimensional viscoelastic model that depicts the viscoelastic detormation behaviour of powder compacts in hot pressing has been developed. It has been shown by the experimental data that the proposed model in which the parameters are determined by means of nonlinear regression analysis can be used to describe the density-time relationship for the hot pressing of pure magnesium oxide and atomized iron powders and to estimate the end-point relative density of the compact.展开更多
In order to understand the influence of nano-sized B4C additive on ZA27 alloy, mechanical and physical properties of ZA27-B4C nanocomposites were investigated in terms of B4C content. While physical properties were de...In order to understand the influence of nano-sized B4C additive on ZA27 alloy, mechanical and physical properties of ZA27-B4C nanocomposites were investigated in terms of B4C content. While physical properties were determined in terms of microstructural studies, density and porosity tests, mechanical properties were determined in terms of ultimate tensile strength（UTS） and hardness experiments. Morphological and microstructural studies were carried out with scanning electron microscopy（SEM）. The experimental results indicate that nano-sized B4C can be used to enhance the mechanical properties of ZA27 alloy effectively. The highest mechanical performance can be obtained at ZA27-0.5% B4C（in weight） nanocomposite with values of tensile strength（247 MPa） and hardness（141,18 BH） and low partial porosity（0.5%）. After a pick point, increasing B4C ratio may cause the formation of agglomeration in grain boundaries, that＇s why density, tensile strength, and hardness values are declined.展开更多
In the present study, pure magnesium was in situ coated with pre-alloyed Al–Cu–Mg alloy through hot pressing. The produced samples were characterized by means of hardness, wear properties and microstructure characte...In the present study, pure magnesium was in situ coated with pre-alloyed Al–Cu–Mg alloy through hot pressing. The produced samples were characterized by means of hardness, wear properties and microstructure characterization. A ball-on-disk test was used to determine the dry sliding wear characteristics of the compacts. The results showed that the hot pressing technique has been successfully applied for producing magnesium parts with compatible wear resistance and hardness to aluminum. The in situ coating of Al on Mg by hot pressing resulted in an increase in hardness of about 30% compared with the pure Mg substrate. The wear rate and friction coefficient of the samples decreased with Al coating and increased with an increase in the applied load during the wear tests, compared with the uncoated material.展开更多
文摘Based on an assumption that the effective pressure in hot pressing related to the applied pressure varies with the relative density of the compact in a power law form. a three-dimensional viscoelastic model that depicts the viscoelastic detormation behaviour of powder compacts in hot pressing has been developed. It has been shown by the experimental data that the proposed model in which the parameters are determined by means of nonlinear regression analysis can be used to describe the density-time relationship for the hot pressing of pure magnesium oxide and atomized iron powders and to estimate the end-point relative density of the compact.
基金Funded by the Research Projects Unit of Karadeniz Technical(Number:12040)TUBITAK(Number:213M276)
文摘In order to understand the influence of nano-sized B4C additive on ZA27 alloy, mechanical and physical properties of ZA27-B4C nanocomposites were investigated in terms of B4C content. While physical properties were determined in terms of microstructural studies, density and porosity tests, mechanical properties were determined in terms of ultimate tensile strength（UTS） and hardness experiments. Morphological and microstructural studies were carried out with scanning electron microscopy（SEM）. The experimental results indicate that nano-sized B4C can be used to enhance the mechanical properties of ZA27 alloy effectively. The highest mechanical performance can be obtained at ZA27-0.5% B4C（in weight） nanocomposite with values of tensile strength（247 MPa） and hardness（141,18 BH） and low partial porosity（0.5%）. After a pick point, increasing B4C ratio may cause the formation of agglomeration in grain boundaries, that＇s why density, tensile strength, and hardness values are declined.
文摘In the present study, pure magnesium was in situ coated with pre-alloyed Al–Cu–Mg alloy through hot pressing. The produced samples were characterized by means of hardness, wear properties and microstructure characterization. A ball-on-disk test was used to determine the dry sliding wear characteristics of the compacts. The results showed that the hot pressing technique has been successfully applied for producing magnesium parts with compatible wear resistance and hardness to aluminum. The in situ coating of Al on Mg by hot pressing resulted in an increase in hardness of about 30% compared with the pure Mg substrate. The wear rate and friction coefficient of the samples decreased with Al coating and increased with an increase in the applied load during the wear tests, compared with the uncoated material.
