Preparation Of Fe-base Alloy With High Performance By Powder Metallurgy Warm Compaction

In this paper, Fe-base alloy materials with high performance were prepared by powder lubrication warm compaction (WC), and the influence of graphite and lubricants on the properties of Fe-base alloys and warm compaction mechanism of the densification process were studied. Under the conditions of compaction pressures of 600 or 800 MPa and compaction temperature of 100 or 120℃, the WC powders containing Distaloy AB powders(commodity name), lubricants, additive, and the WC powders Distaloy AE powders(commodity name), lubricants, additive, both from Sweden Hoganas company (the largest iron powder provider) were pressed respectively, then sintered in the furnace with cracked ammonia atmosphere at 1120℃for half an hour. After that, the density and hardness HRB of sintered materials were measured, and tensile test was done; micro structures were observed by optical microscope and tensile fracture surfaces were observed and analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).Results and analysis of tests show that:1. After the graphite is added, Fe-base alloys contain more complex heterogeneous organizations such as ferrite, pearlite, austenite. strengthening the matrix, which can significantly improve the mechanical properties of Fe-base alloys.2. The lubricant Intralube(commodity name) from Swedish company Hoganas is a good polymer lubricant, under the condition of 100℃or 120℃temperature, which can flow and spread on the powder particles surface, forming a surface lubricating film layer, reducing the friction between the particles so as to strengthen the combination between particles and reduce the porosity and pore size of materials significantly.3. The Distaloy AE powders added 0.6%lubricant Intralube and 0.3%graphite, are formed at a compaction pressure of 800 MPa and compaction temperature of 100℃, and then sintered to obtain Fe-base alloy material with high performance that presents a 7.39g.cm-3 sintered density,92HRB hardness,582MPa yield strength,731MPa ultimate tensile strength and 4.2%elongation, which reachs the standard of Hoganas company. 4. The Distaloy AB powders added 0.6%lubricant Intralube and 0.3%graphite, are formed at a compaction pressure of 800 MPa and compaction temperature of 120℃. and then sintered to obtain Fe-base alloy material with high performance that presents a 7.41 g.cm-3 sintered density,88HRB hardness.573MPa yield strength,606MPa ultimate tensile strength and 2.8%elongation, which reachs the standard of Hoganas company.