Study On Compressive Properties Of An Architecture ZTAp/Steel Composite

In this paper,an architecture ZTAp/steel architected composite(3D-MMC/40Cr)was produced by squeeze casting that combined with 3D printing for to improve mechanical properties of traditional particles reinforced metal matrix composite(PRMMCs),The composite consist of 3D interpenetrating frameworks of 40 Cr steel and ZTA particulates reinforced 40 Cr steel composite,i.e.,40 Cr steel region and ZTAp/40 Cr MMC region.The effects of the volume fraction of ZTAp/40 Cr MMC region,Microstructures and mechanical properties of 40 Cr steel in the composite,ceramic-steel interface bonding and sharp-angled smooth treatment on the compressive mechanical properties of 3D-MMC/40 Cr were investigated.When we studied the effects of the volume fraction of ZTAp/40 Cr MMC region that was designed to 0%(40Cr steel),35%,50%,65% and 100%(ZTA particulates reinforced 40 Cr steel composite),respectively,and all of the specimens has been implemented quenching and low-T tempering treatment.The results showed that the strength of composites presented increasing trend with ZTAp/40 Cr MMC region,it attained maximum while the volume fraction is 35%,then decline gradually,and the toughness also decreased gradually.The yield strength,compressive strength and strain of composite with the volume fraction of 35% is 1455.2MPa,1612.8MPa and 0.056.Compared to 40 Cr steel,yield strength of architected composite was improved 18%;Relative to ZTA particulates reinforced 40 Cr steel composite,its yield strength,compressive strength and strain were improved 144.7%,162.8% and 55.6%.When we studied the effects of the Microstructures and mechanical properties of 40 Cr steel in the composites were varied by different heat treatments,the conditions are quenching + low-T tempering,quenching + medium-T tempering and annealing,respectively.The results showed that the strength of architected composites gradually increased with the strength of 40 Cr steel(Relative to ZTA particulates reinforced 40 Cr steel composite,its compressive strength was improved by 99.5%).The strain in compressive strength of architected composite arrived maximum in condition of quenching + medium-T tempering(Relative to ZTA particulates reinforced 40 Cr steel composite,it was increased by 197.5%),it is better at low matrix strength,but falling sharply at high matrix strength(quenching + low-T tempering).When we studied the effects of the activated elements,ZTAp/40 Cr MMC region added to10%Ti,10% reduced iron powders,20% reduced iron powders and 10%Ti+20% reduced iron powders.The results showed that ZTAp/40 Cr MMC region added to 10% Ti powders for refining the ZTAp-40 Cr interfacial wettability,improved interfacial bonding strength and growed load transfer efficiency,addition of Ti powders gained the highest compressive strength.The addition of reduced iron powders adjusted effectively the volume fraction of ZTAp in MMC region,increased the strain rate.However,10%Ti+20% reduced iron powders did not work very well,there was a slight increase in strain rate.The skeleton of MMC region was designed to be primitive and sharp-angled smoothed treatment.The results showed that sharp-angled smoothed treatment helped to improve the strength ang toughness,its yield strength,compressive strength and strain at compressive strength is 1261.7Mpa and 1426.2Mpa(Compared to primitive,it was increased by 25.2%,16.4% and 22.9%),respectively.And,to be observed microstructures of composites by optimal microscope(OM),the information of cracks distributed in surface and inner of specimens was obtained by scanning electron microscope(SEM)and 3D x-ray computed tomography,analyzed the process of the crack initiation and propagation to explain the synergistic strengthening effect of 40 Cr frameworks and ZTAp/40 Cr MMC region.Finally,finite element simulation was executed to carry out the process from yield stage to failure,revealed the damage behavior of architected composites,the result showed that MMC region had a function of strengthening in elastic stage.But in plastic stage,ultimate failure of composites with particulates breakage and interface of ZTAp-Steel opening,the simulated results matched well with experiment.