模壁润滑对铁基粉末制品力学性能的影响

以成分为Fe-12Cr-2.5W-0.4Ti-0.25(Y2O3)雾化粉末为原料,分别使用聚乙二醇为模壁润滑剂,硬脂酸为粉末润滑剂进行压制。对比了模壁润滑与粉末润滑对模压制品的力学性能影响。研究铁基高温合金粉末模压成形致密化过程中的影响因素和作用机理。研究结果表明:粉末润滑有助于在低压条件下颗粒的重排和致密化,但是其本身占据了压坯的体积从而限制了致密度的进一步提高;采用模壁润滑避免了粉末中混入有机物,使得制备高致密材料成为可能;粉末的退火软化有助于压制成形,并提高合金的致密度;在较高压力下,使用模壁润滑的样品颗粒之间结合更为紧密,孔隙明显减少,这是导致其力学性能提高的主要原因。

Influences of die wall lubrication on mechanical properties of iron-based superalloy powder compacts

The pre-alloyed powder Fe-12Cr-2.5W-0.4Ti-0.25(Y2O3) made by inert-gas atomization was used as raw material,polyethylene glycol and stearic acid were used as the die wall lubricant and admixed powder lubricant,respectively.The influences on mechanical property of die wall lubrication procedure were compared to admixed powder lubrication method.The influencing factors and densification mechanism of iron-based high temperature alloy powder by pressing were investigated.The results show that the lubrication procedure has a great influence on the consolidation and microstructural features.Admixed lubricant aids the densification in the low-pressure region but hinders further densification with the increase of pressure.On the other hand,die wall lubrication offers the possibility of making pore-free material.Powder annealing leads to better ability for plastic deformation and thus aids the densification.It is also found that the particles bind together more tightly by die wall lubrication under higher pressure and the porosity decreases significantly,which leads to better mechanical property.