The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods w...The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.展开更多
The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surfa...The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surface area of 133.7 m^(2)/g.NAPT and DAPT were incorporated into the silicone rubber to obtain the composite NAPTSR and DAPT-SR by mechanical blending method,respectively.After thermal oxidative ageing at 300℃ for 0.5 h,temperature for the 5%weight loss increased greatly from 385℃ of the neat silicone rubber to 396-399℃ with addition of NAPT and DAPT.NAPT and DAPT enhanced the interaction between the filler nanoparticles and rubber matrix thus inhibited the nanoparticle agglomeration.The conservation rate of the side methyl group in NAPT-SR and DAPT-SR was greatly improved after ageing.Therefore,the thermal oxidative degradation and ageing performance of the silicone rubber composites was significantly reinforced.Moreover,DAPT could greatly restrain the growth of nanoparticles after ageing.Therefore,DAPT-SR showed the better retention of tensile strength(40.6%),elongation at break(34.9%)and tear strength(30.1%)compared with the corresponding mechanical properties of the neat silicone rubber(10.6%,7.4%,and 5.0%)after ageing.展开更多
基金supported by the general project of the National Natural Science Foundation of China(No.52071042)Chongqing Natural Science Foundation Project,China(Nos.CSTB2023NSCQ-MSX0079,cstc2021ycjh-bgzxm0148)Graduate Student Innovation Program of Chongqing University of Technology,China(No.gzlcx20232008).
文摘The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear(ES)process,and the microstructure,deformation mechanism,and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses.The experimental results show that the proportion of dynamic recrystallization(DRX)and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress.The texture type of the Al alloys exhibits slight variations at different temperatures.With the increase of temperature,the DRX behavior of Mg alloy shifts from discontinuous DRX(DDRX),continuous DRX(CDRX),and twin-induced DRX(TDRX)dominant to CDRX,the dislocation density in Mg alloy grains decreases significantly,and the average value of Schmid factor(SF)of the basalslip system increases.In particular,partial grains exhibit a distinct dominant slip system at 390℃.The hardness and thickness of the bonding layer,as well as the yield strength and elongation of the Mg alloy,reach their maximum at 360℃as a result of the intricate influence of the combined temperature and shear stress.
基金supported by the Key Special Program on the S&T for the Pollution Control and Treatment of Water Bodies (No.2017ZX07603-003)。
文摘The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surface area of 133.7 m^(2)/g.NAPT and DAPT were incorporated into the silicone rubber to obtain the composite NAPTSR and DAPT-SR by mechanical blending method,respectively.After thermal oxidative ageing at 300℃ for 0.5 h,temperature for the 5%weight loss increased greatly from 385℃ of the neat silicone rubber to 396-399℃ with addition of NAPT and DAPT.NAPT and DAPT enhanced the interaction between the filler nanoparticles and rubber matrix thus inhibited the nanoparticle agglomeration.The conservation rate of the side methyl group in NAPT-SR and DAPT-SR was greatly improved after ageing.Therefore,the thermal oxidative degradation and ageing performance of the silicone rubber composites was significantly reinforced.Moreover,DAPT could greatly restrain the growth of nanoparticles after ageing.Therefore,DAPT-SR showed the better retention of tensile strength(40.6%),elongation at break(34.9%)and tear strength(30.1%)compared with the corresponding mechanical properties of the neat silicone rubber(10.6%,7.4%,and 5.0%)after ageing.
