机构地区: 燕山大学
出 处: 《稀有金属材料与工程》 2008年第A04期712-715,共4页
摘 要: 将0.075mm的Ti,Cu,Ni,Sn4种金属粉按合金成分为Ti50Cu23Ni20Sn7进行配比,并在行星式球磨机中进行机械合金化(MA)球磨。试验中的球磨机转速为300r/m,球料比为10:1。XRD和DSC分析结果表明,经过30h球磨之后,金属粉末已经全部合金化,并且为非晶态结构。继续进行球磨只能减小粉末颗粒尺寸,却会引入更多的杂质,所以30h是制备Ti50Cu23Ni20Sn7非晶合金粉末最为合适的时间。SEM下观察发现,经机械合金化所获得的非晶粉为层状团聚结构。将所制备的非晶合金粉装入碳化钨模具中,并在放电等离子烧结(SPS)设备中进行快速烧结。其烧结的温度分别为480、490、500和510℃,烧结压力为500MPa,保温时间为1min。从XRD和DSC分析结果可以看出,烧结后的合金基体为非晶结构,并伴有少量晶化相。烧结件放在光学显微镜下观察可以看到少许缩孔和疏松等烧结缺陷。将温度为490℃下烧结的试件破碎,并将断口在SEM下观察可以发现,试件断裂方式为层状脆性断裂。试验结果表明采用机械合金化和放电等离子烧结技术可以成功制备出Ti基大块金属玻璃。 Powder metallurgy technologies were developed to prepare Ti50Cu23Ni20Sn7 Bulk Metallic Glasses (BMGs). Firstly, amorphous powder was prepared by mechanical alloying (MA) method successfully. The as-milled amorphous powder was then consolidated by spark-plasma sintering (SPS) method into four specimens with the shape of cylindrical stick, with a diameter and height of about 20 mm and 10 mm respectively. The SPS experiments were conducted under a pressure of 500 MPa at the heating rate of 40 K/min, holding for 1 min at the temperature of 480, 490, 500, and 510 ℃ respectively. Microstructures of the as-milled powder and one consolidated specimen conduced by 490 ℃ were characterized by X-ray diffraction (XRD), optical microscope (OM), and scanning electron microscopy (SEM). Differential scanning calorimeter (DSC) was conducted to examine the thermal stability of the as-milled powder. It was confirmed that the as-milled powder is fully amorphous; however the consolidated specimen shows an amorphous matrix with partial crystallization. Fractograph of the specimen appears to be shear fracture.
关 键 词: 机械合金化 放电等离子烧结 基合金 大块非晶合金 粉末冶金
领 域: [一般工业技术]