金属粉末冲击成形的理论研究

本文应用动力学和流变学探讨了金属粉末冲击成形理论。采用了装有单板计算机的动态测试装置测定落锤冲击粉末体产生的应力、位移和时间。研究结果表明: (1)具有一定动能的落锤产生的最大冲击应力和时间取决于落锤重量、粉末在模具中充填量和粉末体变形程度。粉末体的压制密度取决于最大冲击应力和时间,而与冲击动能无对应关系。 (2)冲击成形的应力和应变关系可以用黄培云教授提出的非线性粘弹方程σ=Mε~m+ηε~K来描述。其中σ为应力,ε为应变,ε为应变速度,M、m、η和k均为常数。采用计算机计算了锡、铜、铁和钼粉的流变参数,计算结果表明,理论计算值和实验测定值吻合良好。

THEORETICAL STUDY ON IMPACT COMPACTION OF METAL POWDERS

A theoretical investigation was made on the impact compaction of metal powders based on thedynamics and rheology. The stress, displacement and acting time exerted on the powder by a drophammer were measured by using a dynamics electrometry controlled by a single board micro-tcomputer. The results obtained are as fol1ows. a) The maximum stress produced by a dropping hammer with a certain kinetic energy and theacting time depend on the hammer weight, the filling weight of the powder in the die and thedegree of the deformation of the powder. The green density depends on the maximum impact stress andacting time, but it does not correspond to the impact kinetic energy. b) The relationship between the stress and strain on impact compaction may be described by thenonlinear visco-elastic model derived by professor Huang Peiyun. The rheologic parameters of Fe,Cu, Sn and Mo powder; are calculated by computer. The calculation show; that theoretical andexperimental data are in satisfactory agreement.