摘要
To clarify the transformation mechanism of secondary phase and the mechanism of intergranular corrosion in laser welding Ni-based alloy (Hastelloy C-276)/304 stainless steel with filler wire,the secondary phase was analyzed by electron probe micro-analysis (EPMA) and transmission electron microscopy (TEM).The evaluation of intergranular corrosion resistance of the welded joints was conducted by double-loop electrochemical potentiokinetic reactivation(DL-EPR) method,and at the same time the chemical compositions of the corrosion surface were analyzed by energy-dispersive spectrometry (EDS).The results show that p phase has complete coherence relationship withμphase,and the coherent relationship is described as[001]p//■and[430]p//[0001]μ.Theμphase is rapidly transformed from p phase,which is the inhomogeneous phase transformation.The transformation of secondary phase will increase the susceptibility to intergranular corrosion.Therefore,the transformation of secondary phase should be avoided in the welding process.
为了阐明激光填丝焊接镍基合金(Hastelloy C-276)/304二次相的转变机制和晶间腐蚀机制,通过EPMA和TEM对二次相进行分析;采用双环动电位再活化法(DL-EPR)对焊接接头的晶间腐蚀性能进行评价,并采用EDS对焊接接头腐蚀表面进行成分分析。实验结果表明:p相和μ相为完全共格关系,且其共格关系为[001]p//■和[430]p//[0001]μ。μ相由p相快速相转变而成,此相变过程为不均匀相变。二次相转变将增大晶间腐蚀敏感性。因此,在焊接过程中应该避免这种相变。
基金
The authors would like to acknowledge the financial support from National Key Research and Development Program of China(2018YFB1107801 and 2018YFB1107802)
Science Fund for Creative Research Groups of NSFC(51621064)
National Natural Science Foundation of China(51790172)
Fundamental Research Funds for the Central University(DUT19LAB06).
