Combined powder metallurgy routes to improve thermal and mechanical response of Al−Sn composite phase change materials  

粉末冶金组合工艺提高Al−Sn复合相变材料的热和力学响应

作　　者：Chiara CONFALONIERI Maxime PERRIN Elisabetta GARIBOLDI 

机构地区：[1]Department of Mechanical Engineering,Politecnico di Milano,Via La Masa 1,20156 Milan,Italy

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第12期3226-3239,共14页中国有色金属学报（英文版）

摘　　要：Powder metallurgy processes are suitable to produce form-stable solid−liquid phase change materials from miscibility gap alloys.They allow to obtain a composite metallic material with good dispersion of low-melting active phase particles in a high-melting passive matrix,preventing leakage of the particles during phase transition and,therefore,increasing the stability of thermal response.Also,the matrix provides structural properties.The aim of this work is to combine conventional powder mixing techniques(simple mixing and ball milling)to improve active phase isolation and mechanical properties of an Al−Sn alloy.As matter of fact,ball milling of Sn powder allows to reduce hardness difference with Al powder;moreover,ball milling of the two powders together results in fine microstructure with improved mechanical properties.In addition,different routes applied showed that thermal response depends on the microstructure and,in particular,on the particle size of the active phase.In more detail,coarse active phase particles provide a fast heat release with small undercooling,while small particles solidify more slowly in a wide range of temperature.On the other hand,melting and,consequently,heat storage are independent of the particle size of the active phase.This potentially allows to“tailor”the thermal response by producing alloys with suitable microstructure.粉末冶金工艺适用于从混溶间隙合金制备形态稳定的固−液相变材料。采用粉末冶金工艺能够获得低熔点活性相颗粒在高熔点惰性基体中分散良好的复合金属材料,防止相变过程中颗粒的离析,从而增加材料热稳定性。组合传统的粉末混合技术(简单混合和球磨)以改善Al−Sn合金的活性相离析和力学性能。事实上,球磨Sn粉可以减少其与Al粉的硬度差异,利用球磨将两种粉末混合会得到细小的显微组织,从而提高力学性能。此外,采用不同的组合方式混粉,热响应取决于显微组织,尤其是活性相颗粒的尺寸。更详细地说,粗大的活性相颗粒可提供快速放热与小的过冷,而小颗粒在大温度范围内凝固更慢。另一方面,活性相颗粒尺寸不会影响熔化和储热。因此,可以通过调控合金的显微组织来调控其热稳定性。

关 键 词：metallic phase change materials powder metallurgy thermal stability mechanical properties miscibility gap alloys 

分 类 号：TB34[一般工业技术—材料科学与工程]