机械合金化制备TiC弥散强化440C不锈钢复合材料

TiC dispersion strengthening 440C stainless steel prepared by mechanical alloying

在440C高铬不锈钢粉末中分别添加25%、35%、45%(体积分数)TiC粉末,利用机械合金化球磨制备复合粉,再经过成形、真空烧结、热等静压等工艺,得到了TiC弥散强化440C不锈钢。通过对试片进行XRD、SEM和激光粒度分析以及视孔隙率、硬度和抗弯强度的测试,研究机械合金化工艺对制备弥散强化复合材料的影响。结果显示,在球磨转速为600 r/min、BPR80、温度30℃、球磨时间16 h的条件下,得到TiC粒径从90μm降至3μm、均匀分布在440C基体中的最佳复合粉。提高真空烧结温度,或再经热等静压处理,都可得到视孔隙率低的合金,合金的硬度与强度提高,其中添加35%TiC,1 300～1 400℃真空烧结以及热等静压处理的合金有较高的硬度与强度。

TiC dispersion strengthening 440C stainless steel composite was prepared using 440C high chromium stainless steel powder with respective addition of 25%, 35%, 45%（volume fraction） TiC powder by the process of ball milling, shaping, vacuum sintering and hot isostatic pressing. The effect of mechanical alloying on the properties of the composites was analyzed by XRD, SEM and measurement for particle size, apparent porosity, hardness, bending strength The results show that on the condition of the milling speed 600 r/min, BPR80, 30 ℃, ball milling time 16 h, the dimension of TiC powder decrease from 90μm to 3μm and TiC distribute uniformly in the composite powder; either improving vacuum sintering temperature or hot isostatic pressing can decrease the porosity and improve the hardness and strength of the composite; after vacuum sintering at 1 300- 1 400 ℃ and hot isostatic pressing, the composite with addition of 35% TiC has the highest hardness and strength.