应力梯度和温度对GH4169高温合金力学性能的影响

Effects of stress gradient and temperature on mechanical properties of GH4169 superalloy

通过对某种特殊冶炼工艺得到的GH4169合金,在550、650、750℃不同温度梯度以及590、690、790 MPa不同应力水平下进行试验,获得了该合金的高温力学性能,对冶炼工艺的优化提供了指导。结果表明,高温拉伸试验中,随着温度的提高,拉伸件的抗拉强度显著降低,延伸率和断面收缩率都有一个小幅度的提高,δ相的析出数量和分布无明显变化,碳化物析出相减少。高温持久试验中,在相同温度下,随着应力增大,持久断裂的时间不断减小;当所受应力相同时,随着温度的增大,持久断裂的时间急剧减小,并给出了γ″相贫瘠的原因。

GH4169 alloy was obtained by a specific metallurgical process and tensile experiments were carried out at different temperature gradients of 550℃,650℃and 750℃and different stress levels of590 MPa,690 MPa and 790 MPa.The mechanical properties of the alloy were obtained,which in turn provided guidance for the optimization of the smelting process.For the elevated temperature tensile test,with the increase of temperature the tensile strength of the steel decreases significantly,while the elongation and area shrinkage rate slightly increase,and no obvious change on the precipitation quantity and distribution ofδphase has been found,but the carbide precipitation phase decreases.During elevated temperature endurance test,at the given temperature with the increase of stress the time of permanent fracture decreases continuously.When the stress is given,with the increase of temperature the time of permanent fracture decreases sharply.Through this research the reason for the impoverishment of theγ"phase is explained.