The effect of Al addition （2 and 5 at. pct） on sintering kinetics of Ti power were investigated. Al reduces the sintering rates, sinter density, increases activation energy of sintering and accelerates the grain gro...The effect of Al addition （2 and 5 at. pct） on sintering kinetics of Ti power were investigated. Al reduces the sintering rates, sinter density, increases activation energy of sintering and accelerates the grain growth. Sintering was controlled by mixed mode, i.e. transient liquid phase sintering, formation of intermetallics, and Ti grain boundary diffusion in TiAl2 and other intermetallics.展开更多
The corrosion behaviour of Hadfield manganese austenitic steel matrix composite reinforced with the varying amount of TiC and unreinforced Hadfield manganese austenitic steel matrix alloy has been evaluated in 3.5% Na...The corrosion behaviour of Hadfield manganese austenitic steel matrix composite reinforced with the varying amount of TiC and unreinforced Hadfield manganese austenitic steel matrix alloy has been evaluated in 3.5% NaCl aqueous solution with the pH value of 6 by the potentiodynamic polarization curves and linear polarization resistance measurements at a scan rate of 1 mV/s at room temperature (25°C ± 2°C). The corrosion rate of the composites is higher than that of their unreinforced matrix alloy and it increases with the increasing volume fraction of TiC. The poor corrosion resistance of the composites can be attributed to the galvanic effects between the matrix and reinforcement.展开更多
Two austenitic Mn steels(Fe-17 Mn and Fe-17 Mn-3 Al(wt%, so as the follows)) were subjected to thermomechanical processing(TMP) consisting of forging followed by solutionization and hot rolling. The rolled samples wer...Two austenitic Mn steels(Fe-17 Mn and Fe-17 Mn-3 Al(wt%, so as the follows)) were subjected to thermomechanical processing(TMP) consisting of forging followed by solutionization and hot rolling. The rolled samples were annealed at 650 and 800°C to relieve the internal stress and to induce recrystallization. The application of TMP and heat treatment to the Fe-17 Mn/Fe-17 Mn-3 Al steels refined the austenite grain size from 169 μm in the as-solutionized state to 9–13 μm, resulting in a substantial increase in hardness from HV 213 to HV 410 for the Fe-17 Mn steel and from HV 210 to HV 387 for the Fe-17 Mn-3 Al steel. The elastic modulus values, as evaluated by the nanoindentation technique, increased from(175 ± 11) to(220 ± 12) GPa and from(163 ± 15) to(205 ± 13) GPa for the Fe-17 Mn and Fe-17 Mn-3 Al steels, respectively. The impact energy of the thermomechanically processed austenitic Mn steels was lower than that of the steels in their as-solutionized state. The addition of Al to the Fe-17 Mn steel decreased the hardness and elastic modulus but increased the impact energy.展开更多
In this study, a series of tests have been conducted in order to investigate the machinability evaluation of austenitic Hadfield manganese steel in the Wire Electrical Discharge Machine (WEDM). Experimental investigat...In this study, a series of tests have been conducted in order to investigate the machinability evaluation of austenitic Hadfield manganese steel in the Wire Electrical Discharge Machine (WEDM). Experimental investigations have been carried out to relate the effect of input machining parameters such as pulse on-time (Ton), pulse off-time (Toff), wire feed (WF), and average gap voltage (V) on the wire offset in WEDM. No analytical approach gives the exact amount of offset required in WEDM and hence experimental study has been undertaken. In this paper, a mathematical model has been developed to model the machinability evaluation through the response surface methodology (RSM) capable of predicting the response parameter as a function of Ton, Toff, WF and V. The samples are tested and their average prediction error has been calculated taking the average of all the individual prediction errors. The result shows that this mathematical model reflects the independent, quadratic and interactive effects of the various machining parameters on cutting speed in WEDM process.展开更多
This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion synthesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and c...This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion synthesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and citric acid, glycine or citric acid plus glycine as fuel. The minimum crystallite size of ceria powder is obtained by combustion synthesis of ceric ammonium nitrate and citric acid. The ceria powder produced by combustion synthesis of ceric ammonium nitrate and citric acid and glycine has less agglomeration of particles than other techniques.展开更多
文摘The effect of Al addition （2 and 5 at. pct） on sintering kinetics of Ti power were investigated. Al reduces the sintering rates, sinter density, increases activation energy of sintering and accelerates the grain growth. Sintering was controlled by mixed mode, i.e. transient liquid phase sintering, formation of intermetallics, and Ti grain boundary diffusion in TiAl2 and other intermetallics.
文摘The corrosion behaviour of Hadfield manganese austenitic steel matrix composite reinforced with the varying amount of TiC and unreinforced Hadfield manganese austenitic steel matrix alloy has been evaluated in 3.5% NaCl aqueous solution with the pH value of 6 by the potentiodynamic polarization curves and linear polarization resistance measurements at a scan rate of 1 mV/s at room temperature (25°C ± 2°C). The corrosion rate of the composites is higher than that of their unreinforced matrix alloy and it increases with the increasing volume fraction of TiC. The poor corrosion resistance of the composites can be attributed to the galvanic effects between the matrix and reinforcement.
文摘Two austenitic Mn steels(Fe-17 Mn and Fe-17 Mn-3 Al(wt%, so as the follows)) were subjected to thermomechanical processing(TMP) consisting of forging followed by solutionization and hot rolling. The rolled samples were annealed at 650 and 800°C to relieve the internal stress and to induce recrystallization. The application of TMP and heat treatment to the Fe-17 Mn/Fe-17 Mn-3 Al steels refined the austenite grain size from 169 μm in the as-solutionized state to 9–13 μm, resulting in a substantial increase in hardness from HV 213 to HV 410 for the Fe-17 Mn steel and from HV 210 to HV 387 for the Fe-17 Mn-3 Al steel. The elastic modulus values, as evaluated by the nanoindentation technique, increased from(175 ± 11) to(220 ± 12) GPa and from(163 ± 15) to(205 ± 13) GPa for the Fe-17 Mn and Fe-17 Mn-3 Al steels, respectively. The impact energy of the thermomechanically processed austenitic Mn steels was lower than that of the steels in their as-solutionized state. The addition of Al to the Fe-17 Mn steel decreased the hardness and elastic modulus but increased the impact energy.
文摘In this study, a series of tests have been conducted in order to investigate the machinability evaluation of austenitic Hadfield manganese steel in the Wire Electrical Discharge Machine (WEDM). Experimental investigations have been carried out to relate the effect of input machining parameters such as pulse on-time (Ton), pulse off-time (Toff), wire feed (WF), and average gap voltage (V) on the wire offset in WEDM. No analytical approach gives the exact amount of offset required in WEDM and hence experimental study has been undertaken. In this paper, a mathematical model has been developed to model the machinability evaluation through the response surface methodology (RSM) capable of predicting the response parameter as a function of Ton, Toff, WF and V. The samples are tested and their average prediction error has been calculated taking the average of all the individual prediction errors. The result shows that this mathematical model reflects the independent, quadratic and interactive effects of the various machining parameters on cutting speed in WEDM process.
文摘This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion synthesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and citric acid, glycine or citric acid plus glycine as fuel. The minimum crystallite size of ceria powder is obtained by combustion synthesis of ceric ammonium nitrate and citric acid. The ceria powder produced by combustion synthesis of ceric ammonium nitrate and citric acid and glycine has less agglomeration of particles than other techniques.
