在厚度为8.0 mm 的AZ31B 镁合金板材上分别进行钨极氩弧焊 TIG 自熔焊和斜 Y 型坡口添丝焊焊接裂纹试验,研究焊接裂纹的产生原因和扩展特征,分析镁合金材料的裂纹敏感性。试验结果表明,在自拘束条件下,自熔焊焊缝区焊后立即产生焊接热裂...在厚度为8.0 mm 的AZ31B 镁合金板材上分别进行钨极氩弧焊 TIG 自熔焊和斜 Y 型坡口添丝焊焊接裂纹试验,研究焊接裂纹的产生原因和扩展特征,分析镁合金材料的裂纹敏感性。试验结果表明,在自拘束条件下,自熔焊焊缝区焊后立即产生焊接热裂纹,斜 Y 型坡口添丝焊焊缝区在焊接电流为170 A 和180 A 的情况下出现焊接热裂纹。自熔焊焊接热裂纹是沿晶扩展,添丝焊焊接热裂纹是沿晶与穿晶的混合扩展,裂纹在扩展过程中都存在分叉裂纹。未出现裂纹的焊接试件放置48 h 后仍然没有观察到任何形式的延迟裂纹。展开更多
Microstructures and crack extending characteristic of the YG8R,YT5R and YT14R hard alloys adding a trace cerium were studied by AEM and HVEM with a tensile holder.In the hard alloys adding cerium,the compounds of Ce_2...Microstructures and crack extending characteristic of the YG8R,YT5R and YT14R hard alloys adding a trace cerium were studied by AEM and HVEM with a tensile holder.In the hard alloys adding cerium,the compounds of Ce_2O_3 or Ce_2O_2S could be formed,extending of stacking faults and transforma- tion from fcc Co to hcp Co were suppressed,volume fraction of fcc Co in the alloys was increased,and strength of Co and(TiW)C phases and grain boundaries were raised.Plastic deformation in Co phase near edges of the tensile cracks was more strong,and the tensile cracks could pass through some smaller WC grains.展开更多
文摘在厚度为8.0 mm 的AZ31B 镁合金板材上分别进行钨极氩弧焊 TIG 自熔焊和斜 Y 型坡口添丝焊焊接裂纹试验,研究焊接裂纹的产生原因和扩展特征,分析镁合金材料的裂纹敏感性。试验结果表明,在自拘束条件下,自熔焊焊缝区焊后立即产生焊接热裂纹,斜 Y 型坡口添丝焊焊缝区在焊接电流为170 A 和180 A 的情况下出现焊接热裂纹。自熔焊焊接热裂纹是沿晶扩展,添丝焊焊接热裂纹是沿晶与穿晶的混合扩展,裂纹在扩展过程中都存在分叉裂纹。未出现裂纹的焊接试件放置48 h 后仍然没有观察到任何形式的延迟裂纹。
文摘Microstructures and crack extending characteristic of the YG8R,YT5R and YT14R hard alloys adding a trace cerium were studied by AEM and HVEM with a tensile holder.In the hard alloys adding cerium,the compounds of Ce_2O_3 or Ce_2O_2S could be formed,extending of stacking faults and transforma- tion from fcc Co to hcp Co were suppressed,volume fraction of fcc Co in the alloys was increased,and strength of Co and(TiW)C phases and grain boundaries were raised.Plastic deformation in Co phase near edges of the tensile cracks was more strong,and the tensile cracks could pass through some smaller WC grains.
