CAJ | 학술논문

通过X射线衍射(XRD)和透射电镜(TEM)研究Cu?20Ni?20Mn合金在450°C时效过程中的显微组织及相转变，并对时效后合金的抗拉强度、屈服强度和硬度进行分析。结果表明，时效开始阶段存在一个很长的孕育期，此时合金的强度和硬度没有明显变化。随着时效时间的延长，有序的面心四方结构(FCT) NiMn相在晶粒中形核并长大。随着有序FCT结构相尺寸的增加，合金硬度和强度提高并达到极大值。在450°C时效40 h后合金强度达到942 MPa。由有序FCT结构NiMn相所产生的沉淀强化是合金主要的时效强化因素。
통과X사선연사(XRD)화투사전경(TEM)연구Cu?20Ni?20Mn합금재450°C시효과정중적현미조직급상전변，병대시효후합금적항랍강도、굴복강도화경도진행분석。결과표명，시효개시계단존재일개흔장적잉육기，차시합금적강도화경도몰유명현변화。수착시효시간적연장，유서적면심사방결구(FCT) NiMn상재정립중형핵병장대。수착유서FCT결구상척촌적증가，합금경도화강도제고병체도겁대치。재450°C시효40 h후합금강도체도942 MPa。유유서FCT결구NiMn상소산생적침정강화시합금주요적시효강화인소。
The microstructure evolution and phase transformation of Cu?20Ni?20Mn (mass fraction, %) alloy at 450 °C were investigated by X-ray diffraction and transmission electron microscopy (TEM). The variations of tensile strength, yield strength and hardness of this alloy during aging process were also analyzed. The results show that no significant variations of hardness and strength in the initial stage of aging, with a long incubation period, are observed at 450 °C. Subsequently, the ordered face-centered tetragonal (FCT) NiMn phase nucleates and grows up with prolonging the aging time. The hardness and tensile strength of the alloy increase up to their maximum values with increasing the ordered particle size, i.e., the strength of the alloy reaches 942 MPa after being aged at 450 °C for 40 h. The main cause of the age-hardening is considered to be precipitation strengthening due to the ordered FCT-NiMn particles.