预扩散及退火对Fe基粉末高速压制成形与烧结性能的影响

Effects of Prediffusion and Annealing on High Speed Pressing and Sintering Properties of Fe Based Powder

分别通过预扩散和退火对Fe粉进行改性处理,结合高速压制工艺制取高密度Fe基粉末冶金材料,研究预扩散及退火对Fe基粉末高速压制成形与烧结性能的影响。结果表明:退火处理改善了粉末的塑性变形能力,在高速压制过程中获得更高的压坯密度。预扩散处理改善了合金元素的分布,使得烧结试样中显微组织更均匀,晶粒更细。退火和预扩散处理都能提升烧结试样的力学性能。在800℃以下,预扩散处理后的烧结试样的力学性能要好于退火处理的力学性能。相较于未处理的试样,预扩散温度为800℃时,烧结试样的表观硬度和抗弯强度分别从55.3 HRB和786.8MPa升高至72.3 HRB和1326.6 MPa。

Fe powders were modified by prediffusion and annealing respectively.High density Fe based powder metallurgy materials were prepared by high speed pressing.The effects of prediffusion and annealing on the high speed pressing and sintering properties of Fe based powder were studied.The results show that,the plastic deformation ability of the powder is improved by annealing treatment.In the process of high speed pressing,a higher compaction density is obtained.The prediffusion treatment improves the distribution of alloying elements and makes the microstructure of the sintered sample more uniform and the grains fine.The mechanical properties of the sintered specimens can be improved by annealing and prediffusion.Below 800℃,the mechanical properties of sintered samples after pre-diffusion treatment are better than those of annealed samples.Compared with untreated samples,the apparent hardness and flexural strength of sintered samples increase from 55.3 HRB and 786.8 MPa to 72.3 HRB and 1326.6 MPa at pre diffusion temperature of 800℃,respectively.