为了扩大不锈钢的应用范围与节省较昂贵的镍资源,笔者以粒径<38.5μm含氮不锈钢粉末和多组元粘结剂(PW,HDPE,SA)为原料,采用粉末注射成形工艺制备了0Cr17Mn12Mo2N含氮无镍奥氏体不锈钢材料,并对其表面状态与显微组织、拉伸断口形貌以及力学性能、耐蚀性能进行了分析与测试。结果表明:使用上述粘结剂能够成功地实现含氮不锈钢粉末的注射成形;在流动N2气氛中,0.1MPa,1340℃下烧结120m in,再经热处理后,注射成形0Cr17Mn12Mo2N不锈钢烧结体的相对密度可达到97.6%,含氮量达到0.83%(质量分数)。该含氮无镍不锈钢具有良好的强度和塑性:抗拉强度σb=910MPa,屈服强度σ0.2=560MPa,伸长率5δ=46%,断面收缩率Ф=39.5%,硬度(HRB)为91.7,各项性能指标均优异于M IM 316L不锈钢。
The experiments of heat treatment,hot extrusion and hard drawing were employed to study their effects on the structure and mechanical properties of Mg-9Al-1.2Nd-0.45Y-0.7Zn magnesium alloy. The results indicate that the mechanical properties of the ingot are unstable and exhibit typical brittle failure. After heat treatment(693 K,24 h),most β-Mg17Al12 phases decomposed into the α-Mg matrix and the distribution of Rare earths compounds remained the state of as-cast,which have little effects of the mechanical properties of the alloy. As the casting defects disappeared and the grain was refined after hot extruded,the mechanical properties of the alloy were drastically increased. By hard drawing,the ultimate tensile strength and the yield strength of the alloy were sharply increased while the elongation decreased rapidly. The failure of as-cast samples was mainly brittle fracture. After plastic deformation,the fracture patterns all exhibited ductile rupture features.
