Laser technology holds significant promise for enhancing rock-breaking efficiency.Experimental investigations were carried out on sandstone subjected to laser radiation,aiming to elucidate its response mechanism to su...Laser technology holds significant promise for enhancing rock-breaking efficiency.Experimental investigations were carried out on sandstone subjected to laser radiation,aiming to elucidate its response mechanism to such radiation.The uniaxial compressive strength of sandstone notably decreases by 22.1%–54.7%following exposure to a 750 W laser for 30 s,indicating a substantial weakening effect.Furthermore,the elastic modulus and Poisson ratio of sandstone exhibit an average decrease of 33.7%and 25.9%,respectively.Simultaneously,laser radiation reduces the brittleness of sandstone,increases the dissipated energy proportion,and shifts the failure mode from tensile to tension-shear composite failure.Following laser radiation,both the number and energy of acoustic emission events in the sandstone register a substantial increase,with a more dispersed distribution of these events.In summary,laser radiation induces notable damage to the mechanical properties of sandstone,leading to a substantial decrease in elastic energy storage capacity.Laser rock breaking technology is expected to be applied in hard rock breaking engineering to significantly reduce the difficulty of rock breaking and improve rock breaking efficiency.展开更多
The dynamic recrystallization behavior of high strength steel during hot deformation was investigated.The hot compression test was conducted in the temperature range of 950-1150 °C under strain rates of 0.1,1 and...The dynamic recrystallization behavior of high strength steel during hot deformation was investigated.The hot compression test was conducted in the temperature range of 950-1150 °C under strain rates of 0.1,1 and 5 s-1.It is observed that dynamic recrystallization(DRX) is the main flow softening mechanism and the flow stress increases with decreasing temperature and increasing strain rate.The relationship between material constants(Q,n,α and ln A) and strain is identified by the sixth order polynomial fit.The constitutive model is developed to predict the flow stress of the material incorporating the strain softening effect and verified.Moreover,the critical characteristics of DRX are extracted from the stress-strain curves under different deformation conditions by linear regression.The dynamic recrystallization volume fraction decreases with increasing strain rate at a constant temperature or decreasing deformation temperature under a constant strain rate.The kinetics of DRX increases with increasing deformation temperature or strain rate.展开更多
基金Projects(52225403,U2013603,42377143)supported by the National Natural Science Foundation of ChinaProject(2023NSFSC0004)supported by the Sichuan Science and Technology Program,China+1 种基金Project(2023YFB2390200)supported by the National Key R&D Program-Young Scientist Program,ChinaProject(RCJC20210706091948015)supported by the Shenzhen Science Foundation for Distinguished Young Scholars,China。
文摘Laser technology holds significant promise for enhancing rock-breaking efficiency.Experimental investigations were carried out on sandstone subjected to laser radiation,aiming to elucidate its response mechanism to such radiation.The uniaxial compressive strength of sandstone notably decreases by 22.1%–54.7%following exposure to a 750 W laser for 30 s,indicating a substantial weakening effect.Furthermore,the elastic modulus and Poisson ratio of sandstone exhibit an average decrease of 33.7%and 25.9%,respectively.Simultaneously,laser radiation reduces the brittleness of sandstone,increases the dissipated energy proportion,and shifts the failure mode from tensile to tension-shear composite failure.Following laser radiation,both the number and energy of acoustic emission events in the sandstone register a substantial increase,with a more dispersed distribution of these events.In summary,laser radiation induces notable damage to the mechanical properties of sandstone,leading to a substantial decrease in elastic energy storage capacity.Laser rock breaking technology is expected to be applied in hard rock breaking engineering to significantly reduce the difficulty of rock breaking and improve rock breaking efficiency.
基金Project (51322405) supported by the National Natural Science Foundation of ChinaProject (CX2013B085) supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘The dynamic recrystallization behavior of high strength steel during hot deformation was investigated.The hot compression test was conducted in the temperature range of 950-1150 °C under strain rates of 0.1,1 and 5 s-1.It is observed that dynamic recrystallization(DRX) is the main flow softening mechanism and the flow stress increases with decreasing temperature and increasing strain rate.The relationship between material constants(Q,n,α and ln A) and strain is identified by the sixth order polynomial fit.The constitutive model is developed to predict the flow stress of the material incorporating the strain softening effect and verified.Moreover,the critical characteristics of DRX are extracted from the stress-strain curves under different deformation conditions by linear regression.The dynamic recrystallization volume fraction decreases with increasing strain rate at a constant temperature or decreasing deformation temperature under a constant strain rate.The kinetics of DRX increases with increasing deformation temperature or strain rate.
