不锈钢金属多孔材料固相烧结热变形特性研究  

Study of Thermal Deformation Characteristics of Solid Phase Sintering of Stainless Steel Metal Porous Materials

作　　者：杜艳迎[1] 刘凯[1] Du Yanying;Liu Kai(Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学,湖北武汉430070

出　　处：《稀有金属材料与工程》2022年第7期2552-2559,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(U1806221)。

摘　　要：烧结工艺对多孔材料性能有很大的影响,为了获得最佳的力学性能和需要的零件形状,有必要对烧结的热变形过程进行研究。基于SVOS粘塑性本构模型,采用热力耦合计算不锈钢多孔材料在烧结过程中宏观变形。通过自由烧结实验和弯曲实验,使用4阶Gauss函数对烧结应力、体积和剪切粘度等模型参数进行了拟合。讨论了相对密度、线性收缩率等随烧结时间和温度的变化规律。结果表明:模拟过程与实验符合得较好,验证了模型的合理性。不同升温速率下,材料的线性收缩曲线变化不大,因此,升温速率对烧结过程影响较小。升温速率对计算时间影响比较大,升温速率很慢或很快时,计算不容易收敛,计算时间比较长。对模压生坯零件的烧结模拟结果表明,由于初始密度分布不均匀性导致最终密度分布的不均匀,但是密度变化范围不大。Sintering process has great influence on the performance of porous materials. In order to obtain the best mechanical properties and required parts shape, it is necessary to study the thermal deformation evolution of sintering. Based on coupled thermo-mechanical SVOS visco-plastic constitutive model, the macro deformation of stainless steel porous materials during sintering process was calculated. The parameters of sintering stress, shear viscosity and volume modulus were fitted by fourth-order Gauss functions based on free sintering and bending experiments. The changes of relative density, linear shrinkage rate with the sintering time and temperature were discussed. The results show that the simulated process is consistent with the experiments, validating the rationality of the model. The difference of linear contraction curves under different heating rates of material is very little. Therefore, heating rate has little influence on sintering process. The heating rate has a great influence on the calculation time. When the heating rate is very slow or fast, computations are not easy to converge, and the calculation time is longer. The sintering simulations of the green parts prepared by dry-press process show that the initial density distribution inhomogeneity causes eventually density distribution inhomogeneity, while the range of density is not large.

关 键 词：烧结 数值模拟 SVOS模型 致密化 

分 类 号：TH164[机械工程—机械制造及自动化]