Abstract

In this study, open-cell steel foams containing 0.6 wt% carbon and 2 wt% phosphorous have been manufactured through powder metallurgy route using urea granules as leachable space holder. Influences of applied pressure (100, 150, and 200 MPa), sintering temperature (1050, 1100, and 1150 °C), and sintering time (40, 50, and 60 min) on size and sphericity of the cells, pores specifications, porosity percentage, thickness and microstructure of the cells walls, and mechanical properties of the steel foam specimens were investigated. The microstructures of the cells walls were evaluated using optical microscopy and scanning electron microscopy equipped image processing software. To study the mechanical properties, compressive tests were conducted on the steel foam specimens. The averages of cells diameter, sphericity of cells, and thickness of cells walls were measured to be 0.78 mm, 0.842, and 183 µm, respectively. When the production parameters increase, the mean diameter of the pores decreases and the mean sphericity of the pores increases. Increasing the applied pressure, sintering temperature, and sintering time reduces, individually, the porosity percentage from 79.32 to 73.61%, 77.01 to 75.81%, and 77.81 to 75.12%, respectively. The microstructure of the cells walls consists of ferrite, pearlite, and iron-phosphorous phase. Iron-phosphorous phase formed at boundaries of agglomerated iron particles improves bonding, due to liquid phase sintering. Elastic region, long saw-toothed plateau region, and fracture point are observed in compressive stress versus strain curves. Increasing the applied pressure, sintering temperature, and sintering time enhances the plateau stress and absorb energy of the steel foams.

Graphic Abstract

摘要

在这项研究中，已经通过使用尿素颗粒作为可浸出的空间保持器的粉末冶金路线制造了含有0.6 wt％的碳和2 wt％的磷的开孔钢泡沫。施加压力（100、150和200 MPa），烧结温度（1050、1100和1150°C）和烧结时间（40、50和60分钟）对泡孔尺寸和球形度，孔规格的影响研究了泡沫壁样品的孔隙率，厚度和微结构，以及泡沫塑料的力学性能。细胞壁的微观结构使用光学显微镜和配备扫描电子显微镜的图像处理软件进行评估。为了研究机械性能，对泡沫钢样品进行了压缩测试。细胞直径，细胞球形度的平均值，细胞壁的厚度和厚度分别为0.78mm，0.842和183μm。当生产参数增加时，孔的平均直径减小，并且孔的平均球形度增加。施加压力，烧结温度和烧结时间的增加分别将孔隙率分别从79.32降低到73.61％，77.01降低到75.81％和77.81降低到75.12％。孔壁的微观结构由铁素体，珠光体和铁-磷相组成。由于液相烧结，在团聚的铁颗粒的边界处形成的铁-磷相改善了结合。在压缩应力与应变曲线中观察到了弹性区域，长锯齿状的平台区域和断裂点。增加施加压力，烧结温度，

图形摘要