Influence of the Pore Characteristics on Mechanical Properties and Abrasive Wear of Sintered Iron-Based Alloys Subjected to a Thermochemical Treatment

摘要

The aim of this paper is to analyse the effect of the pore morphology on microstructural characteristics, mechanical properties and abrasive wear resistance of iron-based alloys subjected to a thermochemical treatment as carburizing in fluidized bed. The starting materials studied in this paper are represented by pre-alloyed iron base powder obtained by powder metallurgy (P/M) route. The powders were produced by water atomization with different particle sizes (< 45, 45-63, 63-100, 100-150, >150 μm). The raw powders have been mixed with 1% zinc stearate as lubricant and uniaxially compacted into cylindrical specimens at room temperature at 600 MPa. The disc dimensions are Φ8 × 6 mm. The green compacts were sintered at 1.150°C for 90 minutes in a laboratory furnnace. After sintering, a thermochemical treatment was applied. The parameters for the carburizinng in fluidized bed are: temperature of 930°C and time of 45 minutes. The microstructural characterization was carried out using optical microscopy. The porosity of studied samples were analyzed acording to their microstructural characteristics and chemical composition. The mechanical properties and abrasive wear of the sintered and thermochemical treated samples were evaluated. A correlation between porosity, mechanical properties and abrasive wear was established.