The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO_3blends are investigated. Not all HDPE can be toughened by CaCO_3 particles. The ability of thematrix to yield plays a fundamental ro...The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO_3blends are investigated. Not all HDPE can be toughened by CaCO_3 particles. The ability of thematrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (I_(sc)≈45J/m) below which HDPE can not be toughenedobservably by CaCO_3 particle at given average size, and above which the critical matrix ligamentthickness (τ_?) is proportional to matrix impact strength.展开更多
It is of great significance to investigate effect of multiple heat treatments on fracture property of centrifugal casting stainless steels Z3CN20.09M cut from pump casing with long-term thermal aging degradation for n...It is of great significance to investigate effect of multiple heat treatments on fracture property of centrifugal casting stainless steels Z3CN20.09M cut from pump casing with long-term thermal aging degradation for nuclear power plants to consider actual operation of nuclear power plants.Both multiple heat treatments and accelerated thermal aging experiment at the same temperature of 400℃ for different time were successively carried out on centrifugal casting stainless steels Z3CN20.09M in order to examine the metallographic modification and impact properties.Finally,an additional investigation on the related fracture properties was carried out,in which the critical initial fracture toughness Ji was determined by stretch zone width and 0.2 mm offset line methods.These results indicated that the multiple heat treatments led to the dispersed distribution of ferrite phases in austenite matrix and thus microhardness increased,but impact energy exhibited a decreasing tendency significantly.After long-term aging,the metallographic structure remained almost unchanged,but the size of ferrite phases showed a slight increasing trend because of spinodal decomposition in ferrite phases and G-phase precipitation.In addition,centrifugal casting stainless steels Z3CN20.09M with multiple heat treatments exhibited the higher microhardness,Charpy impact toughness,critical initial fracture toughness J_(IC)(J-integral determined by 0.2 mm offset line method),and J_(SZW)(J-integral determined by stretch zone width method)than those with primary heat treatment,while the specific number of the heat treatment had a low influence on fracture toughness.展开更多
基金This project is supported by the National Natural Science Foundation of China.
文摘The effects of HDPE matrix toughness on the brittle-ductile transition of HDPE/CaCO_3blends are investigated. Not all HDPE can be toughened by CaCO_3 particles. The ability of thematrix to yield plays a fundamental role in determing whether HDPE can be toughened or not.There exists a critical matrix toughness (I_(sc)≈45J/m) below which HDPE can not be toughenedobservably by CaCO_3 particle at given average size, and above which the critical matrix ligamentthickness (τ_?) is proportional to matrix impact strength.
基金supported by the National Key Research and Development Program of China(No.2017YFB0702200)the Natural Science Foundation of Jiangsu Province(No.BK20171223 and BK20170383).
文摘It is of great significance to investigate effect of multiple heat treatments on fracture property of centrifugal casting stainless steels Z3CN20.09M cut from pump casing with long-term thermal aging degradation for nuclear power plants to consider actual operation of nuclear power plants.Both multiple heat treatments and accelerated thermal aging experiment at the same temperature of 400℃ for different time were successively carried out on centrifugal casting stainless steels Z3CN20.09M in order to examine the metallographic modification and impact properties.Finally,an additional investigation on the related fracture properties was carried out,in which the critical initial fracture toughness Ji was determined by stretch zone width and 0.2 mm offset line methods.These results indicated that the multiple heat treatments led to the dispersed distribution of ferrite phases in austenite matrix and thus microhardness increased,but impact energy exhibited a decreasing tendency significantly.After long-term aging,the metallographic structure remained almost unchanged,but the size of ferrite phases showed a slight increasing trend because of spinodal decomposition in ferrite phases and G-phase precipitation.In addition,centrifugal casting stainless steels Z3CN20.09M with multiple heat treatments exhibited the higher microhardness,Charpy impact toughness,critical initial fracture toughness J_(IC)(J-integral determined by 0.2 mm offset line method),and J_(SZW)(J-integral determined by stretch zone width method)than those with primary heat treatment,while the specific number of the heat treatment had a low influence on fracture toughness.
