热处理工艺对ZTAp/HCCI复合材料组织及耐磨性能的影响

Effect of heat treatment process on microstructure and wear resistance of ZTAp/HCCI composites

首先将1~2 mm的ZTA(ZrO_(2)增韧Al_(2)O_(3))颗粒、高铬铸铁(HCCI)粉末和粘结剂混合并压制,随后在真空下烧结制备出蜂窝状预制体,最后将高铬铸铁液浇注到预制体中制备出了ZTA颗粒增强高铬铸铁(ZTAp/HCCI)复合材料。将复合材料在940、980、1020和1060℃下淬火,确定最佳淬火温度后分别在220、320、420和520℃下回火,研究了不同热处理工艺对复合材料微观组织及三体磨料磨损性能的影响。结果表明:复合材料经1020℃淬火+420℃回火后的高铬铸铁基体组织最佳,为回火马氏体、残留奥氏体、共晶碳化物及二次碳化物,柱状区和复合区基体硬度最高为63.03和55.95 HRC,三体磨损试验累计体积损失最小为120.28 mm^(3),复合材料耐磨性能与热处理后高铬铸铁基体硬度正相关。

Firstly, 1-2 mm ZTA(ZrOtoughened AlO) ceramic particles, high chromium cast iron(HCCI) powder and adhesives were mixed and pressed, and then sintered under vacuum to prepare honeycomb preform. Finally, the high chromium cast iron liquid was poured into the preform to prepare ZTA particle reinforced high chromium cast iron(ZTAp/HCCI) composites. Firstly, the composites were quenched at 940, 980, 1020 and 1060 ℃ to determine the optimal quenching temperature. Then the samples quenched at the optimal quenching temperature were tempered at 220, 320, 420 and 520 ℃ respectively. The effects of different heat treatment processes on microstructure and three-body abrasive wear properties of the composites were studied. The results show that the microstructure of high chromium cast iron matrix of the composites after quenching at 1020 ℃ and tempering at 420 ℃ is the best, which is tempered martensite, retained austenite, eutectic carbide and secondary carbide. The maximum matrix hardness of columnar zone and composite zone is 63.03 and 55.95 HRC, and the minimum accumulative volume loss of three-body wear test is 120.28 mm^(3). The wear resistance of the composites is positively related to the hardness of high chromium cast iron matrix after heat treatment.