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含20(wt)％Ag的Pt—Ag合金是一种物理、化学和机械综合性能良好的弹性材料,常用来制作高级电表等精密仪表的关键元件。但是,该合金塑性差,特别是铸锭在开坯过程中易开裂,因而无论制作该合金线材或片材都较为困难。该文主要是作者多年来试制PtAg20合金材料的经验总结,并从熔炼到加工详细地介绍了一种较为成熟的制作PtAg20合金片材的新工艺,对该合金的组织结构和某些性能也做了简单介绍。文章指出,铸锭中的严重的枝晶偏析、气泡等缺陷存在,以及合金固态下的有序相转变是造成该合金加工中开裂的主要原因。并指出,该合金熔炼过程中,采用于1 x10-1乇低真空度下除气、500乇氩气保护下精炼及水冷铜模浇铸等措施,可获得高质量的锭坯;为了防止开坯时,铸锭严重开裂现象,开坯前将铸锭于950℃下进行均匀处理是必要的;在加工过程中,除精心操作,合理分配和严格控制变形量外,还应配合有适当的热处理制度,以防止发生有序相转变,并可进一步消除枝晶偏析。文章最后指出,该合金具有优良的机械特性主要依赖于时效强化,600℃时效态I-lv可达347kg/mm2。
Pt-Ag alloy containing 20 wt% Ag is a kind of elastic material with good physical, chemical and mechanical properties. It is often used to make the key components of precision instruments such as advanced ammeters. However, the alloy is poor in plasticity, especially when the ingot is easy to crack during the billet formation, making it difficult to make the alloy wire or sheet. This paper mainly summarizes the experience of the author in trialing and manufacturing PtAg20 alloy for many years and introduces a more mature new process of making PtAg20 alloy sheet from melting to processing. The structure and some properties of the alloy are also made A brief introduction. The article points out that the severe dendritic segregation, bubbles and other defects in the ingot, as well as the ordered phase transition of the alloy solid state is the main reason for cracking in the processing of the alloy. And pointed out that the alloy melting process, the use of 1 x10-1 Torr under low vacuum degassing, 500 torr under argon protection and water-cooled copper mold casting and other measures to obtain high-quality billet; in order to prevent billet , Severe ingot ingot cracking occurs. It is necessary to uniformly treat the ingot at 950 ° C before slabbing. In addition to meticulous operation, rational distribution and strict control of the deformation, a suitable heat treatment System to prevent the occurrence of ordered phase transitions and to further eliminate dendrite segregation. Finally, the article pointed out that the alloy has excellent mechanical properties mainly depends on aging strengthening, 600 ℃ aging I-lv up to 347kg / mm2.