10 k V母线受潮可能导致绝缘降低,发生放电故障,严重时可能造成设备烧毁、主变低压侧保护动作导致整条母线失压的事故。10 k V母线受潮主要是因为开关柜内部的湿度过高。现对开关柜内部湿度过高的原因进行了分析,列举了几种常规的预防方...10 k V母线受潮可能导致绝缘降低,发生放电故障,严重时可能造成设备烧毁、主变低压侧保护动作导致整条母线失压的事故。10 k V母线受潮主要是因为开关柜内部的湿度过高。现对开关柜内部湿度过高的原因进行了分析,列举了几种常规的预防方法,并对采用半导体制冷的新除湿技术进行了重点介绍。展开更多
W-（0.2,0.5,1.0）wt%ZrC alloys with a relative density above 97.5%were fabricated through the spark plasma sintering（SPS） method.The grain size of W-1.0wt%ZrC is about2.7 μm,smaller than that of pure W and W-（0.2,...W-（0.2,0.5,1.0）wt%ZrC alloys with a relative density above 97.5%were fabricated through the spark plasma sintering（SPS） method.The grain size of W-1.0wt%ZrC is about2.7 μm,smaller than that of pure W and W-（0.2,0.5）wt%ZrC.The results indicated that the W-ZrC alloys exhibit higher hardness at room temperature,higher tensile strength at high temperature,and a lower ductile to brittle transition temperature（DBTT） than pure W.The tensile strength and total elongation of W-0.5wt%ZrC alloy at 700 ℃ is 535 MPa and 24.8%,which are respectively 59%and 114%higher than those of pure W（337 MPa,11.6%）.The DBTT of W-（0.2,0.5,1.0）wt%ZrC materials is in the range of 500 ℃-600 ℃,which is about 100 ℃ lower than that of pure W.Based on microstructure analysis,the improved mechanical properties of the W-ZrC alloys were suggested to originate from the enhanced grain boundary cohesion by ZrC capturing the impurity oxygen in tungsten and nano-size ZrC dispersion strengthening.展开更多
基金supported by the Innovation Program of Chinese Academy of Sciences(No.KJCX2-YW-N35)the National Magnetic Confinement Fusion Science Program of China(No.2011GB108004)+1 种基金National Natural Science Foundation of China(Nos.51301164,11075177,11274305)Anhui Provincial Natural Science Foundation of China(No.1408085QE77)
文摘W-（0.2,0.5,1.0）wt%ZrC alloys with a relative density above 97.5%were fabricated through the spark plasma sintering（SPS） method.The grain size of W-1.0wt%ZrC is about2.7 μm,smaller than that of pure W and W-（0.2,0.5）wt%ZrC.The results indicated that the W-ZrC alloys exhibit higher hardness at room temperature,higher tensile strength at high temperature,and a lower ductile to brittle transition temperature（DBTT） than pure W.The tensile strength and total elongation of W-0.5wt%ZrC alloy at 700 ℃ is 535 MPa and 24.8%,which are respectively 59%and 114%higher than those of pure W（337 MPa,11.6%）.The DBTT of W-（0.2,0.5,1.0）wt%ZrC materials is in the range of 500 ℃-600 ℃,which is about 100 ℃ lower than that of pure W.Based on microstructure analysis,the improved mechanical properties of the W-ZrC alloys were suggested to originate from the enhanced grain boundary cohesion by ZrC capturing the impurity oxygen in tungsten and nano-size ZrC dispersion strengthening.
