Warm surface rolling is a working process between room temperature and re-crystallization temperature.With warm surface rolling of steel grade 45 grooved axle,its fatigue lifespan was measured by the endurance bending...Warm surface rolling is a working process between room temperature and re-crystallization temperature.With warm surface rolling of steel grade 45 grooved axle,its fatigue lifespan was measured by the endurance bending test.The influence of surface rolling reduction on the axle fatigue life period was experimentally studied at different surface rolling temperatures.The experimental results show that the fatigue life of the steel axles can be significantly improved by the warm surface rolling process.The optimum rolling reductions for the maximum fatigue life at different warm surface rolling temperatures were explored.The microstructures of the steel axles were analyzed.The surface strength improved by refining grains after the warm surface rolling was calculated by the Hall-Petch model.These research achievements could be also valuable to the relevant works.展开更多
Insulated gate bipolar transistor(IGBT)power module is used for power switching transistor devices in the power supply and motor control circuits in both hybrid electric vehicles and electric vehicles.The target of he...Insulated gate bipolar transistor(IGBT)power module is used for power switching transistor devices in the power supply and motor control circuits in both hybrid electric vehicles and electric vehicles.The target of heat flux of IGBT is continuously increasing due to the demand for power rating improvements and miniaturisation.Without suitable efficient cooling technolo-gies,excessively high temperature and uneven temperature distribution can cause high thermal stress,eventually leading to severe module failures.Therefore,highly efficient cooling solutions are highly required.Vapour chamber with phase change can provide quick heat transfer and low temperature gradient.This study proposes a new IGBT structure integrated with vapour chamber.The tests and simulation results indicate that the thermal and thermo-mechanical performances of IGBT integrated with vapour chamber are better than those of the IGBT with copper baseplate module.The thermal resistance between the junction and heat sink is reduced from 0.25 to 0.14°C/W,and the temperature uniformity is greatly improved due to the phase change in the vapour chamber.The simulation also investigates the thermal stress distribution,deformation and thermal fatigue lifespan of IGBT power electronics module.A reduction of 21.8%in thermal stress and an increase of 9%in lifespan of Sn-3.5Ag solder are achieved.展开更多
文摘Warm surface rolling is a working process between room temperature and re-crystallization temperature.With warm surface rolling of steel grade 45 grooved axle,its fatigue lifespan was measured by the endurance bending test.The influence of surface rolling reduction on the axle fatigue life period was experimentally studied at different surface rolling temperatures.The experimental results show that the fatigue life of the steel axles can be significantly improved by the warm surface rolling process.The optimum rolling reductions for the maximum fatigue life at different warm surface rolling temperatures were explored.The microstructures of the steel axles were analyzed.The surface strength improved by refining grains after the warm surface rolling was calculated by the Hall-Petch model.These research achievements could be also valuable to the relevant works.
基金The authors would like to acknowledge the supports from EU H2020-MSCA-RISE project(Ref.778104)of Smart thermal management of high power microprocessors using phase-change(ThermaSMART)Innovate UK&APC ACeDrive Project(Ref.113167)。
文摘Insulated gate bipolar transistor(IGBT)power module is used for power switching transistor devices in the power supply and motor control circuits in both hybrid electric vehicles and electric vehicles.The target of heat flux of IGBT is continuously increasing due to the demand for power rating improvements and miniaturisation.Without suitable efficient cooling technolo-gies,excessively high temperature and uneven temperature distribution can cause high thermal stress,eventually leading to severe module failures.Therefore,highly efficient cooling solutions are highly required.Vapour chamber with phase change can provide quick heat transfer and low temperature gradient.This study proposes a new IGBT structure integrated with vapour chamber.The tests and simulation results indicate that the thermal and thermo-mechanical performances of IGBT integrated with vapour chamber are better than those of the IGBT with copper baseplate module.The thermal resistance between the junction and heat sink is reduced from 0.25 to 0.14°C/W,and the temperature uniformity is greatly improved due to the phase change in the vapour chamber.The simulation also investigates the thermal stress distribution,deformation and thermal fatigue lifespan of IGBT power electronics module.A reduction of 21.8%in thermal stress and an increase of 9%in lifespan of Sn-3.5Ag solder are achieved.
