Sn对铜合金激光选区熔化微熔池组织及性能的影响

Effect of Sn Content on Micro Molten Pool Microstructure and Mechanical Properties of Selective Laser Melted Cu Alloys

优化激光选区熔化(SLM)功率、扫速、扫描间距参数调控策略,使Cu-5%Sn、Cu-15%Sn和Cu-24.6%Sn(质量分数)合金成形致密度分别达99.2%、99.7%和99.7%。发现该SLM成形凝固相转变行为与显微组织均有非平衡凝固特征,α相Cu-5%Sn合金中主要为α-Cu(Sn)固溶体相,α相Cu-15%Sn合金中为α-Cu(Sn)与δ-Cu41Sn11两相,β相Cu-24.6%Sn合金中β相不完全分解而析出γ与δ相。Sn含量由5%增至15%,抗拉强度由384 MPa增至695 MPa,但断裂总延伸率由22.7%降至12%,α相中未见明显择优取向,β相Cu-24.6%Sn合金中有织构与SLM堆积方向平行,拉伸性能呈现强各向异性。

Selective Laser Melting(SLM)was used to prepare Cu-Sn alloys with optimized parameters such as laser power,scanning speed and hatching space and forming density of SLM built Cu-5%Sn,Cu-15%Sn and Cu-24.6%Sn(mass fraction)reaches 99.2%,99.7%,and 99.7%respectively.It is found that solidification phase transformation and microstructure show non-equilibrium characteristics.αphase Cu-5%Sn alloy contains mainlyα-Cu(Sn)solid solution phase,whileαphase Cu-15%Sn alloy is composed ofα-Cu(Sn)andδ-Cu41Sn11 phases,andβphase Cu-24.6%Sn alloy has partially decomposed toγandδphases.As Sn content rises from 5%to 15%,tensile strength increases from 384 MPa to 695 MPa,while fracture extension drops from 22.7%to 12%.No obvious preferred orientation exists inαCu-Sn alloys,while texture parallel to building direction of SLM appears inβCu-24.6%Sn alloy with strong anisotropy in tensile properties.