High boron iron-based alloy,a new kind of wear-resistant material was developed,and its microstructure and mechanical properties were studied. Moreover,the modification with V,Ti and RE-Mg was carried out as well. The...High boron iron-based alloy,a new kind of wear-resistant material was developed,and its microstructure and mechanical properties were studied. Moreover,the modification with V,Ti and RE-Mg was carried out as well. The results indicate that the high boron iron-based alloy comprises a dendritic matrix and interdendritic eutectic borides under as-cast condition. The matrix is made up of fine pearlite,and the eutectic boride has a crystal structure of M2B （M represents Fe,Cr or Mn）. The boride has a microhardness of HV 1 425 and is distributed in the form of continuous network,which is detrimental to the toughness of high boron iron-based alloy. Nevertheless,high boron iron-based alloy has a higher toughness than that of white cast iron,which is attributed to the matrix that is made up of lath-type martensite with high toughness. In order to increase the toughness further,V,Ti and RE-Mg were adopted to improve the morphology of boride. The results indicate that after modification the matrix grain is decreased in size by half,and the size of boride is also decreased,moreover,it is distributed more even though it is still continuous. After heat treatment,the boride network is break up and results in the further improvement of toughness of high boron iron-based alloy.展开更多
A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring o...A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.展开更多
基金Sponsored by National Key Technologies Research and Development Program of China (2005BA324C)
文摘High boron iron-based alloy,a new kind of wear-resistant material was developed,and its microstructure and mechanical properties were studied. Moreover,the modification with V,Ti and RE-Mg was carried out as well. The results indicate that the high boron iron-based alloy comprises a dendritic matrix and interdendritic eutectic borides under as-cast condition. The matrix is made up of fine pearlite,and the eutectic boride has a crystal structure of M2B （M represents Fe,Cr or Mn）. The boride has a microhardness of HV 1 425 and is distributed in the form of continuous network,which is detrimental to the toughness of high boron iron-based alloy. Nevertheless,high boron iron-based alloy has a higher toughness than that of white cast iron,which is attributed to the matrix that is made up of lath-type martensite with high toughness. In order to increase the toughness further,V,Ti and RE-Mg were adopted to improve the morphology of boride. The results indicate that after modification the matrix grain is decreased in size by half,and the size of boride is also decreased,moreover,it is distributed more even though it is still continuous. After heat treatment,the boride network is break up and results in the further improvement of toughness of high boron iron-based alloy.
文摘A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.
