一种Ni-Cr-Mo镍基合金焊丝凝固过程元素偏析及相转变规律研究

Study on solidification segregation and phase transformation of a Ni-Cr-Mo alloy filler wire

为了对Ni-Cr-Mo镍基合金焊丝进行成分优化设计,本文通过热力学模拟计算方法研究了镍基合金焊丝凝固过程元素的偏析规律,并分析了合金元素对析出相的影响。研究表明:镍基合金焊丝平衡态主要的析出相为γ、M_(6)C、P和μ相;在非平衡凝固状态下,随着凝固过程的推进从液相中析出M_(6)C、P和σ相;随着Cr含量的增加,μ相的初始析出温度和析出量降低,P相的析出温度区间扩大且析出量增加;Mo含量的增加提高了μ相的初始析出温度,扩大了P相的析出温度区间,但对μ相的析出量无明显影响;M_(6)C碳化物的析出温度和析出量则主要受C元素含量的影响;Cr、Mo和W含量的增加不仅改变了TCP相的析出温度区间和析出量,而且提高了M_(6)C型碳化物的初始析出温度。

In order to optimize the composition of Ni-Cr-Mo nickel-base alloy filler wire,the element segregation law during solidification was studied by thermodynamic calculation method,and the influence of alloying element on the precipitates was analyzed.Results showed that the main precipitates wereγ,M_(6)C,P,andμphases at the equilibrium state of the filler wire.M_(6)C,P,andσphases were precipitated from the liquid phase at the non-equilibrium solidification state.With the increase in Cr content,the initial precipitation temperature and precipitation amount ofμphase were reduced,whereas the precipitation temperature range of P phase was widened and the precipitation amount was increased.With the increase in Mo content,the initial precipitation temperature ofμphase was increased and the precipitation temperature range of P phase was widened,while the precipitation amount ofμphase was little affected.The precipitation temperature and precipitation amount of M_(6)C carbides were mainly affected by the content of C element.With the increase in Cr,Mo,and W content,the precipitation temperature range and precipitation amount of TCP phase were changed and the initial precipitation temperature of M_(6)C-type carbides was increased.