Transformation of cast A356 ingots to wrought sheets with enhanced mechanical and tribological properties by different thermo-mechanical processing routes
Transformation of cast A356 ingots to wrought sheets with enhanced mechanical and tribological properties by different thermo-mechanical processing routes
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DOI：
10.1016/j.matdes.2016.03.125
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发表时间：
2016-07
影响因子：
8.4
通讯作者：
R. Immanuel;S. Panigrahi
中科院分区：
文献类型：
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作者：
R. Immanuel;S. Panigrahi
Al-Si合金枝晶组织中硬质第二相颗粒分布不均匀，降低了合金的力学性能和摩擦学性能。强塑性变形是细化组织、提高材料性能的有效方法。在本研究中，采用两种不同的热机械加工路线对铸造亚共晶Al单键Si合金进行加工，以生产具有细化组织的变形板。在一种加工路线中，材料在固溶处理之后经受低温轧制，而在另一种路线中，材料在固溶处理和低温轧制之间经受热处理。低温轧制对材料施加严重的塑性变形，导致第二相颗粒的细化和再分布，从而提高强度和延展性。预辊热处理的冷轧导致比未经热处理的材料更细的晶粒结构。采用销盘摩擦磨损试验方法研究了加工后材料的摩擦学性能，并与基体材料进行了比较。在热处理材料中观察到最大耐磨性，然后是预辊热处理的冷辊材料。热处理后材料的磨损由粘着磨损向氧化剥层磨损转变是其耐磨性提高的主要原因。基于微观组织演变和力学性能，详细解释了所涉及的各种磨损机制。
The dendritic microstructure with non-uniform distribution of hard second phase particles degrades the mechanical and tribological properties of Alsingle bondSi alloys. Severe plastic deformation methods are found effective in refining microstructure and enhancing the material properties. In our present study, two different thermo-mechanical processing routes were employed on a cast hypo-eutectic Alsingle bondSi alloy to produce wrought sheets with refined microstructure. In one processing route, the material is subjected to cryorolling after solution treatment and in the other route, the material is subjected to a thermal-treatment between solution treatment and cryorolling. Cryorolling imposes severe plastic deformation onto the material resulting in refinement and redistribution of second phase particles leading to enhanced strength and ductility. Cryorolling with pre-roll thermal-treatment resulted in finer grain structures than the material without thermal-treatment. The tribological behaviour of processed materials are studied and compared with the base materials by pin-on-disk method. Maximum wear resistance is observed in thermal-treated material followed by cryorolled material with pre-roll thermal-treatment. Transformation from adhesion wear to oxidative-delamination wear is found to be the primary reason for the enhanced wear resistance in thermal-treated material. The various wear mechanisms involved are explained in detail based on the microstructural evolution and mechanical properties.