Investigation of secondary phases and tensile strength of nitrogen-containing Alloy 718 weldment  

作　　者：Behrooz Nabavi Massoud Goodarzi Abdul Khaliq Khan 

机构地区：[1]School of Metallurgy and Materials Engineering,Iran University of Science and Technology,Tehran 1684613114,Iran [2]Department of Mechanical Engineering,Manitoba Institute for Materials,University of Manitoba,Winnipeg R3T 2N2,Canada

出　　处：《International Journal of Minerals,Metallurgy and Materials》2020年第9期1259-1268,共10页矿物冶金与材料学报（英文版）

基　　金：The authors would like to acknowledge Iran University of Science and Technology for financial support。

摘　　要：The influence of nitrogen content on the precipitation of secondary phases and the tensile strength of Alloy 718 during gas tungstenarc welding was investigated. Various types of precipitates were characterized using scanning electron microscopy and transmission electronmicroscopy. The results showed that in the fusion zone, the volume fraction of Nb-rich phases such as Laves, (Nb,Ti)C, and δ phases, as wellas Ti-rich phases such as (Ti,Nb)CN and (Ti,Nb)N, increased with increase in the nitrogen content due to the microsegregation of Nb and Tiwithin interdendritic areas. Nitrogen was also found to decrease the size of γ′′ particles within γ dendrites. For precipitates in the partiallymelted zone, constitutional liquation was observed for both (Nb,Ti)C and (Ti,Nb)N particles. Based on the results of tensile tests, the weld containing0.015wt% nitrogen exhibited the highest ultimate tensile strength (UTS), whereas more addition of nitrogen led to a decrease in both theUTS and yield strength due to the increased content of brittle Laves phases and decreased size of γ′′.

关 键 词：NITROGEN secondary phases gas tungsten arc welding tensile strength Alloy 718 

分 类 号：TG113[金属学及工艺—物理冶金]