喷射沉积SiCp/Al-Fe-V-Si板坯楔形压制后轧制的 显微组织与断裂行为

来源期刊:中国有色金属学报2014年第8期

论文作者:贺毅强 胡建斌 张 奕 陈志钢 冯立超 陈振华

文章页码:2035 - 2044

关键词:耐热铝合金;复合材料;喷射沉积;楔形压制;轧制

Key words:heat resistant aluminium alloy; composite; spray deposition; wedge pressing; rolling

摘    要:采用喷射沉积工艺制备SiCp/Al-8.5Fe-1.3V-1.7Si复合材料板坯,并通过楔形压制后多道次热轧制备复合材料板材。研究板坯在楔形压制和轧制过程中孔洞、SiC分布、弥散粒子的变化和SiC-Al界面特征,并通过X射线衍射和能谱分析板坯材在致密化过程中的物相组成。结果表明,楔形压制工艺能使喷射沉积板坯有效致密化,且能使SiC颗粒均匀分布;板坯经480 ℃下多道次楔形压制和多道次轧制后,弥散粒子依然保持在60~150 nm,未见明显长大,且未向Al13Fe4等平衡相转变,SiC-Al界面处存在一层平直的、宽度为3~5 nm的过渡层,界面干净且没有缺陷,纳米过渡层可以提高界面润湿性;楔形压制后再轧制板材在拉伸过程中的断裂表面呈SiC颗粒限制下的韧性断裂方式,随拉伸温度的升高SiC-Al界面强度降低,当拉伸温度低于200 ℃时,SiC颗粒的拔断为主要裂纹源,当拉伸温度高于200 ℃时,SiC-Al界面脱粘为主要裂纹源。

Abstract: SiCp/Al-8.5Fe-1.3V-1.7Si composite prepared by spray deposition was densified by wedge pressing, and then was hot-rolled into sheets. The evolutions of pore, SiC particles distribution, second-phase dispersions during wedge pressing and SiC/Al interface of composite sheet as-rolled were observed. The phase compositions of composite plate blank during densification process were analyzed by X-ray diffraction and energy spectrum. The results show that the composite plate blank can be densified by wedge pressing, and homogeneous SiC particle distribution can be obtained. The dispersions keep fine with 60-150 nm in diameter from growing obviously and transforming into equilibrium phase such as Al13Fe4 during the wedge pressing and rolling at 480 ℃. A clean SiC-Al interface without defect of the composite sheet as-rolled can be seen, which contributes to the wettability between SiC particle and Al matrix. The tensile fracture surface of the composite as-rolled is characterized with a ductile rupture mechanism under the restriction of SiC particles. The bonding between SiC particle and Al matrix becomes week as tensile temperature increases. Cracks nucleate in the SiC particles as tensile temperature is below 200 ℃, while cracks nucleate along SiC-Al interface as tensile temperature increases up to 200 ℃.

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