预热处理对GH4698合金微观组织及性能的影响  

Effect of Pre-heat Treatment on Microstructure and Properties of GH4698 Alloy

作　　者：江权安 黄亮[1] 李中豪 班宜杰 高首磊 JIANG Quanan;HUANG Liang;LI Zhonghao;BAN Yijie;GAO Shoulei(State Key Laboratory of Materials Processing and Die&Mould Technology,School of Material Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Daye Special Steel Co.,Ltd.,Hubei Huangshi 435001,China)

机构地区：[1]华中科技大学材料科学与工程学院材料成形与模具技术全国重点实验室,武汉430074 [2]大冶特殊钢有限公司,湖北黄石435001

出　　处：《精密成形工程》2025年第2期141-149,共9页Journal of Netshape Forming Engineering

基　　金：国家重点研发计划(2022YFB3706901,2022YFB3706903);湖北省重点研发计划(2022BAA024)。

摘　　要：目的针对锻后GH4698合金组织分布不均匀造成综合力学性能难以平衡的问题,提出通过预热处理来对合金的组织和性能进行优化,并深入探究不同预热处理制度对GH4698合金组织演化和性能的影响。方法在标准四段式热处理之前增加预热处理实验(1173~1273 K,2~8 h),观察不同预热处理条件下GH4698合金析出相尺寸和形貌,采用拉伸实验机与维氏硬度计获得不同预热处理条件下GH4698合金的力学性能,结合拉伸试样断口形貌,分析GH4698合金的断裂机制。结果当预热处理温度为1223 K时,合金内部大γ′相分布均匀,且小γ′相析出量达到峰值,尺寸为15~25 nm;在所研究的预热处理温度和时间范围内,GH4698合金的屈服强度、抗拉强度、延伸率和维氏硬度均呈现先上升后下降的趋势。GH4698合金的断裂形式为沿晶断裂+韧窝的混合断裂模式。结论预热处理温度和时间对γ′相的形貌、尺寸及数量有着显著的影响,相较于未经预热处理的试样,最优的预热处理参数(1223 K/4 h)下的合金屈服强度、抗拉强度、延伸率和维氏硬度分别提升了5.06%、5.48%、3.29%和10.30%。The work aims to propose a pre-heat treatment method to optimize the microstructure and properties of the alloy and delve into the influence of different pre-heat treatment regimes on the microstructural evolution and performance of GH4698 alloy,so as to address the challenge of unbalanced comprehensive mechanical properties resulting from uneven micro-structure distribution in post-forged GH4698 alloy.Pre-heat treatment experiments(1173-1273 K,2-8 h)were conducted prior to the standard four-step heat treatment.The size and morphology of the precipitated phases in GH4698 alloy under various pre-heat treatment conditions were observed.A tensile testing machine and a Vickers hardness tester were used to obtain the mechanical properties of GH4698 alloy under different pre-heat treatment conditions,and the fracture mechanisms were ana-lyzed based on the fracture morphology of the tensile specimens.When the pre-heat treatment temperature was 1223 K,the largeγ′phases were uniformly distributed within the alloy,accompanied by a peak precipitation of smallγ′phases with sizes ranging from 15 to 25 nm.Within the studied range of pre-heat treatment temperatures and times,the yield strength,tensile strength,elongation,and Vickers hardness of GH4698 alloy initially increased and then decreased.The fracture mode of the al-loy exhibited a mixed mode of intergranular fracture and dimple fracture.In conclusion,the pre-heat treatment temperature and time significantly impact the morphology,size,and quantity ofγ′phases.Compared with untreated samples,the alloy under op-timal pre-heat treatment parameters(1223 K/4 h)shows improvements of 5.06%,5.48%,3.29%,and 10.30%in yield strength,tensile strength,elongation,and Vickers hardness,respectively.

关 键 词：GH4698 预热处理 微观组织 力学性能 

分 类 号：TG132.32[一般工业技术—材料科学与工程] TG156.99[金属学及工艺—合金]