ABSTRACT The use of nanopolycrystalline diamond has allowed a systematic study on deformation of polycrystalline diamond composites (PCDCs). Bulk PCDCs samples containing either Co or SiC as a binding agent were deformed under high pressure and temperature to strains up to 18% at strain rates ∼10−5 s−1. All samples exhibit strong work hardening. The strength of PCDCs depends on the amount and type of binding agents and is consistently weaker than that of diamond single crystals. The weakening may be due to the binder materials, which play an important role in affecting grain boundary structures. In SiC-based PCDC, significant grain fragmentation occurs. Nearly all grain boundaries are wetted by SiC after large deformation, resulting in lower strength. In Co-based PCDC, the microstructure is dominated by dislocations, deformation twins, and separated grain boundaries. The density of deformation twins increases significantly with strain, with the twin domain width reaching as low as 10–20 nm at 14% strain.

中文翻译：

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聚晶金刚石复合材料的强度和塑性变形

摘要 纳米多晶金刚石的使用使得对多晶金刚石复合材料 (PCDC) 变形的系统研究成为可能。含有 Co 或 SiC 作为粘合剂的大块 PCDCs 样品在高压和高温下变形至应变率高达 18% 的应变率约为 10-5 s-1。所有样品都表现出强烈的加工硬化。PCDC 的强度取决于粘合剂的数量和类型，并且始终比金刚石单晶弱。弱化可能是由于粘合剂材料在影响晶界结构方面起着重要作用。在基于 SiC 的 PCDC 中，会发生显着的晶粒破碎。大变形后几乎所有晶界都被SiC润湿，导致强度降低。在 Co 基 PCDC 中，微观结构以位错、变形孪晶、和分离的晶界。变形孪晶的密度随应变显着增加，孪晶域宽度在 14% 应变下可低至 10-20 nm。