Strong and tough steel Ultrahard materials often do not have similarly impressive fracture toughness. Liu et al. discovered a processing route for medium manganese steel alloy in which ultrahigh strength accompanies high fracture toughness. The steel relies on both transformation-induced plasticity and delamination toughening to boost the fracture properties. The steel is composed of less expensive elements, making it a potentially inexpensive material attractive for structural applications. Science, this issue p. 1347 Grain boundary delamination confers an ultrahigh-strength steel with very high toughness as well. Developing ultrahigh-strength steels that are ductile, fracture resistant, and cost effective would be attractive for a variety of structural applications. We show that improved fracture resistance in a steel with an ultrahigh yield strength of nearly 2 gigapascals can be achieved by activating delamination toughening coupled with transformation-induced plasticity. Delamination toughening associated with intensive but controlled cracking at manganese-enriched prior-austenite grain boundaries normal to the primary fracture surface dramatically improves the overall fracture resistance. As a result, fracture under plane-strain conditions is automatically transformed into a series of fracture processes in “parallel” plane-stress conditions through the thickness. The present “high-strength induced multidelamination” strategy offers a different pathway to develop engineering materials with ultrahigh strength and superior toughness at economical materials cost.

中文翻译：

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通过晶界分层使超强钢变得坚韧

坚固而坚韧的钢 超硬材料通常没有同样令人印象深刻的断裂韧性。刘等人。发现了超高强度同时具有高断裂韧性的中锰钢合金加工路线。该钢依靠相变诱导塑性和分层韧化来提高断裂性能。钢由较便宜的元素组成，使其成为对结构应用有吸引力的潜在廉价材料。科学，这个问题 p。1347 晶界分层赋予超高强度钢以极高的韧性。开发具有延展性、抗断裂性和成本效益的超高强度钢将对各种结构应用具有吸引力。我们表明，通过激活分层增韧和相变诱导塑性，可以提高钢的抗断裂性，该钢具有接近 2 吉帕的超高屈服强度。分层增韧与在与主断裂表面垂直的富锰原奥氏体晶界处发生强烈但受控的开裂，显着提高了整体抗断裂性。结果，平面应变条件下的断裂自动转化为沿厚度方向“平行”平面应力条件下的一系列断裂过程。目前的“高强度诱导多层分层”策略为以经济的材料成本开发具有超高强度和优异韧性的工程材料提供了不同的途径。