针对6082铝合金的磨损、腐蚀、掉块等损伤,采用CMT(Cold metal transfer)电弧增材再制造技术和自主研发的Al-Si-Cr-Er丝材在其表面制备了单层多道、多层单道及多层多道成形层。综合运用金相显微镜、扫描电子显微镜、万能力学实验机、电...针对6082铝合金的磨损、腐蚀、掉块等损伤,采用CMT(Cold metal transfer)电弧增材再制造技术和自主研发的Al-Si-Cr-Er丝材在其表面制备了单层多道、多层单道及多层多道成形层。综合运用金相显微镜、扫描电子显微镜、万能力学实验机、电化学工作站等分析成形层微观组织并评价其力学及电化学等综合性能。结果表明:成形层平滑光亮,焊道和焊道之间搭接平整紧密,无气孔、热裂纹、咬边、焊瘤等缺陷,Cr及稀土元素Er的加入,有效抑制了晶粒长大,促进了成形组织细化。相较于通用ER4043丝材,Al-Si-Cr-Er成形层的平均抗拉强度达228.7 MPa,最高延伸率达13.5%,微孔聚集形韧窝断裂是其主要失效机制;自腐蚀电位提高了约0.2 V,自腐蚀电流密度降低了一个数量级,成形组织的细化和杂质元素含量的降低是其耐腐蚀性能提升的主要原因。展开更多
Objective: To evaluate various types of samples from the different marine environments as sources of actinomycetes from the Yalujiang coastal wetland, North China, and to screen their antimicrobial properties. Further...Objective: To evaluate various types of samples from the different marine environments as sources of actinomycetes from the Yalujiang coastal wetland, North China, and to screen their antimicrobial properties. Further, the identified actinomycetes were characterized based on morphological, biochemical, and physiological characteristics.Methods: Eight different production media were used to isolate actinomycets from different stations of marine soil sediments in Yalujiang coastal wetland and the genotypic positions were established by 16 S r DNA.Results: A total of 172 actinomycetal isolates were obtained from 13 samples using five media. The most effective culture media in the isolation of actinobacteria were Gause's Synthetic agar and Starch-casein agar. Among 172 isolates, 46 isolates(26.74%) showed antibacterial activity, 70.93% belonged to the genus Streptomyces, others were Micromonospora spp. and Rhodococcus spp. Out of the 46 isolates, two cultures were further supported by morphological characterization analysis.Conclusions: This is the first report about actinomycetes isolated from Yalujiang coastal wetland and it seems that the promising isolates from the unusual/unexplored wetland may prove to be an important step in the development of microbial natural product research.展开更多
文摘针对6082铝合金的磨损、腐蚀、掉块等损伤,采用CMT(Cold metal transfer)电弧增材再制造技术和自主研发的Al-Si-Cr-Er丝材在其表面制备了单层多道、多层单道及多层多道成形层。综合运用金相显微镜、扫描电子显微镜、万能力学实验机、电化学工作站等分析成形层微观组织并评价其力学及电化学等综合性能。结果表明:成形层平滑光亮,焊道和焊道之间搭接平整紧密,无气孔、热裂纹、咬边、焊瘤等缺陷,Cr及稀土元素Er的加入,有效抑制了晶粒长大,促进了成形组织细化。相较于通用ER4043丝材,Al-Si-Cr-Er成形层的平均抗拉强度达228.7 MPa,最高延伸率达13.5%,微孔聚集形韧窝断裂是其主要失效机制;自腐蚀电位提高了约0.2 V,自腐蚀电流密度降低了一个数量级,成形组织的细化和杂质元素含量的降低是其耐腐蚀性能提升的主要原因。
基金Supported by the State Natural Sciences Foundation(No.31270057,No.21276047 and No.31070005)collaboration projects supported by Natural Science Foundation of China and Korea Research Foundation(No.31311140255 and No.2013K2A2A2000535)the Fundamental Research Funds for the Central Universities(DC201501020201)
文摘Objective: To evaluate various types of samples from the different marine environments as sources of actinomycetes from the Yalujiang coastal wetland, North China, and to screen their antimicrobial properties. Further, the identified actinomycetes were characterized based on morphological, biochemical, and physiological characteristics.Methods: Eight different production media were used to isolate actinomycets from different stations of marine soil sediments in Yalujiang coastal wetland and the genotypic positions were established by 16 S r DNA.Results: A total of 172 actinomycetal isolates were obtained from 13 samples using five media. The most effective culture media in the isolation of actinobacteria were Gause's Synthetic agar and Starch-casein agar. Among 172 isolates, 46 isolates(26.74%) showed antibacterial activity, 70.93% belonged to the genus Streptomyces, others were Micromonospora spp. and Rhodococcus spp. Out of the 46 isolates, two cultures were further supported by morphological characterization analysis.Conclusions: This is the first report about actinomycetes isolated from Yalujiang coastal wetland and it seems that the promising isolates from the unusual/unexplored wetland may prove to be an important step in the development of microbial natural product research.
