(1. 大連海事大學(xué) 輪機(jī)工程學(xué)院，大連 116026；
2. 大連海洋大學(xué) 機(jī)械與動(dòng)力工程學(xué)院，大連 116023)
摘 要: 為分析Fe-Mn-Si記憶合金的疲勞特性，采用與該材料具有相同母相的304不銹鋼作為對(duì)比材料，通過(guò)彎曲疲勞試驗(yàn)法測(cè)量?jī)烧咴趹?yīng)變幅值為±3.5%時(shí)的疲勞斷裂次數(shù)，并利用X射線(xiàn)衍射法(XRD)和場(chǎng)發(fā)射掃描電鏡(SEM)分析試樣相組成和斷口形貌。結(jié)果表明：Fe-Mn-Si記憶合金和304不銹鋼的彎曲疲勞斷裂次數(shù)分別為1159次和63次，斷口形貌依次為韌窩和撕裂棱。前者斷裂時(shí)的物相基本為ε馬氏體，而后者幾乎全部由α′馬氏體組成，表明應(yīng)力誘發(fā)Fe-Mn-Si記憶合金發(fā)生γ→ε馬氏體相變。相變過(guò)程中，應(yīng)力集中程度和裂紋擴(kuò)展速度降低是Fe-Mn-Si記憶合金疲勞強(qiáng)度提高的機(jī)理。
關(guān)鍵字: Fe-Mn-Si記憶合金；疲勞特性；γ→ε馬氏體相變
（1. College of Marine Engineering, Dalian Maritime University, Dalian 116026, China;
2. Mechanical and Power Engineering College, Dalian Ocean University, Dalian 116023，China）
Abstract:In order to analyze the fatigue properties of Fe-Mn-Si memory alloy, the 304 stainless steel that had the same parent phase was chosen as contrast material. The fatigue cycles were measured by bending fatigue test under the ±3.5% strain amplitudes, and the phase compositions and fractures appearances of specimens were observed with X-ray diffraction (XRD) and field emission scanning electron microscope (SEM). The experimental results show that the bending fatigue break cycles of Fe-Mn-Si memory alloy and 304 stain steel is 1159 and 63, respectively, their fracture appearances are dimples and tearing ridges in turn. When the specimens break, the former phase compositions are almost ε-martensite, while the latter were basically composed by α′-martensite. The phenomenon indicates that the bending stress induces the γ→ε martensite phase transformation of Fe-Mn-Si memory alloy, and the mechanism of fatigue strength improvement inside Fe-Mn-Si memory alloy is that stress concentration and crack speed reduce in the phase transition process.
Key words: Fe-Mn-Si memory alloy; fatigue properties; γ→ε martensite phase transformatio
