The effect of size and distribution of titanium carbide on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C-0.2Si (mass fraction, %) was investigated. The microstructu...The effect of size and distribution of titanium carbide on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C-0.2Si (mass fraction, %) was investigated. The microstructure of the heat-treated and exposed alloy was studied using optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). It is found that carbides with finer size and more uniform distribution can suppress the formation of α precipitates more effectively, and can especially decrease the amount of grain boundary α precipitates after long-term exposure at 540℃ (the expected application temperature). Thus, significant improvement in thermal stability can be achieved by refining carbide particles in the matrix of the alloy.展开更多
The next generation of nuclear power plants is likely to require production in limited time-scales to meet the shortfall in power generating capacity as ageing power plants are taken off-line. The reactor pressure ves...The next generation of nuclear power plants is likely to require production in limited time-scales to meet the shortfall in power generating capacity as ageing power plants are taken off-line. The reactor pressure vessel lies at the heart of a light water reactor and can take a number of years to manufacture. This paper reviews the current methods employed for the construction of these major vessels and the issues with this route of production. Possible alternatives to traditional methods are briefly reviewed and found to offer their own challenges to achieving a vessel with high demonstrable structural integrity.展开更多
Additively manufacturing(AM)has been used to manufacture fine structures with structured/engineered porosity in heat management devices.In this study,laser powder bed fusion(LPBF)was used to manufacture a high-perform...Additively manufacturing(AM)has been used to manufacture fine structures with structured/engineered porosity in heat management devices.In this study,laser powder bed fusion(LPBF)was used to manufacture a high-performance Ni-superalloy heat pipe,through tailoring LPBF process parameters to fabricate thin wall and micro-channel.By using novel laser scanning strategies,wick structure heat pipes with maximised surface-area-to-volume ratio,fine features size around 100µm,and controlled porosity were successfully fabricated.Microscopy and X-ray microtomography(micro-CT)were used to investigate the 3D structure of the void space within the pipe.Wick test results showed that most of the heat pipes made by LPBF had better performance than the conventionally manufactured pipes.This study also investigated the influences of the process parameters on the porosity volume fraction and the feature size.The results showed that LPBF process could fabricate thin structure due to the change of melt pool contact angle.The relationship between process parameters and bead size reported in this study could help design and manufacture heat pipe with complex fine structure.展开更多
基金Project(2000 2005) supported by Beijing Institute of Aeronautical Materials in China and Rolls-Royce Plc in UK
文摘The effect of size and distribution of titanium carbide on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C-0.2Si (mass fraction, %) was investigated. The microstructure of the heat-treated and exposed alloy was studied using optical microscopy(OM), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). It is found that carbides with finer size and more uniform distribution can suppress the formation of α precipitates more effectively, and can especially decrease the amount of grain boundary α precipitates after long-term exposure at 540℃ (the expected application temperature). Thus, significant improvement in thermal stability can be achieved by refining carbide particles in the matrix of the alloy.
文摘The next generation of nuclear power plants is likely to require production in limited time-scales to meet the shortfall in power generating capacity as ageing power plants are taken off-line. The reactor pressure vessel lies at the heart of a light water reactor and can take a number of years to manufacture. This paper reviews the current methods employed for the construction of these major vessels and the issues with this route of production. Possible alternatives to traditional methods are briefly reviewed and found to offer their own challenges to achieving a vessel with high demonstrable structural integrity.
基金The authors would like to acknowledge Rolls-Royce plc,Aerospace Technology Institute,and Innovate UK for funding this research through the Advanced Repair Technologies(113015)programmeThe CT scans were performed in the University of Manchester,which was established through EPSRC Grants EP/F007906/1,EP/I02249X/1 and EP/F028431/1HMXIF is a part of the Henry Royce Institute for Advanced Materials,established through EPSRC Grants EP/R00661X/1,EP/P025498/1 and EP/P025021/1."。
文摘Additively manufacturing(AM)has been used to manufacture fine structures with structured/engineered porosity in heat management devices.In this study,laser powder bed fusion(LPBF)was used to manufacture a high-performance Ni-superalloy heat pipe,through tailoring LPBF process parameters to fabricate thin wall and micro-channel.By using novel laser scanning strategies,wick structure heat pipes with maximised surface-area-to-volume ratio,fine features size around 100µm,and controlled porosity were successfully fabricated.Microscopy and X-ray microtomography(micro-CT)were used to investigate the 3D structure of the void space within the pipe.Wick test results showed that most of the heat pipes made by LPBF had better performance than the conventionally manufactured pipes.This study also investigated the influences of the process parameters on the porosity volume fraction and the feature size.The results showed that LPBF process could fabricate thin structure due to the change of melt pool contact angle.The relationship between process parameters and bead size reported in this study could help design and manufacture heat pipe with complex fine structure.
