Study Of Titanium/Steel Hot-Compression Bonding Process And Microstructure Properties

Titanium/steel composites have great potential for applications in the energy,transportation,marine and aerospace sectors due to combining corrosion resistance,high specific strength and also excellent mechanical properties.Composite plate and composite tube forming technology is now relatively mature,the preparation of heterogeneous and shaped structural parts and simplified composite forming process has become a research hotspot in the field of titanium/steel composites in recent years.Hot compression bonding has unique advantages in forming large size and heterogeneous structural parts,and has achieved good engineering applications in the field of homogeneous material solid bonding.Therefore,in this paper,10 Cr Ni Cu low-alloy steel and commercially pure titanium TA3 are selected as raw materials to carry out a basic study of the titanium/steel hot compression bonding process and microstructure properties based on physical simulation.It is expected to provide guidance for the preparation of subsequent titanium/steel composites for largesize shaped structural parts.The main research content is as follows:Study of titanium/steel hot compression bonding process: The microstructure and mechanical properties of the interfaces were investigated under different process conditions.The experiments were conducted using the Gleeble-3500 thermal simulation tester for different deformation amounts(30 %,50 % and 70 %)and deformation temperatures(800 °C,850 °C,900 °C,950 °C and 1000 °C).The results show that the bonding can be successfully made when the deformation amount is 30-50 %,and too much deformation will lead to cracks at the interface and thus damage the interface performance.Using the TA3 phase transition temperature as the boundary,the optimal tensile performance is obtained at 850 °C for the bonding below the phase transition point,and the tensile strength of the interface can reach 489 MPa;the optimal tensile performance is obtained at 1000 °C for the bonding above the phase transition point,and the tensile strength of the interface can reach 523 MPa.Effect of annealing and holding treatment on the microstructure and strength of the titanium/steel interface: The microstructure and bond strength of the titanium/steel composite interface were investigated after annealing for different times and temperatures and holding treatment at high temperature for a short time after hot compression bonding at850 °C.The results showed that the interfacial plasticity was greatly improved after annealing.The tensile fracture occurred in the steel side of the matrix after 1-4 h of low temperature annealing at 450 °C.The interfacial strength of the samples held at 850-950 °C for 1 h decreased significantly to a maximum of 324 MPa,and the samples at 850 °C were unable to resist the tangential forces during turning and fracture.Effect of interlayer on titanium/steel interface bonding: The effect of interlayer on titanium/steel composite interface was studied with pure V and pure Ni monometallic interlayer;Ni/V and Ni/Cu/V composite interlayer.The results show that V can form a continuous solid solution with TA3,Ni can form a continuous solid solution with 10 Cr Ni Cu,and Ni/Cu/V form a continuous solid solution between each other;after holding the samples,Fe V and VC phases are formed at the vanadium/steel interface,and V-Ni intermetallic compounds and carbides are formed at the Ni/V interface,while the Ni/Cu/V interface remains free of compounds.